diff --git a/cluster-autoscaler/clusterstate/clusterstate.go b/cluster-autoscaler/clusterstate/clusterstate.go
index 9665d83a431e..dc8d50093221 100644
--- a/cluster-autoscaler/clusterstate/clusterstate.go
+++ b/cluster-autoscaler/clusterstate/clusterstate.go
@@ -648,8 +648,9 @@ func (csr *ClusterStateRegistry) updateIncorrectNodeGroupSizes(currentTime time.
 			}
 			continue
 		}
-		if len(readiness.Registered) > acceptableRange.MaxNodes ||
-			len(readiness.Registered) < acceptableRange.MinNodes {
+		unregisteredNodes := len(readiness.Unregistered) + len(readiness.LongUnregistered)
+		if len(readiness.Registered) > acceptableRange.CurrentTarget ||
+			len(readiness.Registered) < acceptableRange.CurrentTarget-unregisteredNodes {
 			incorrect := IncorrectNodeGroupSize{
 				CurrentSize:   len(readiness.Registered),
 				ExpectedSize:  acceptableRange.CurrentTarget,
diff --git a/cluster-autoscaler/clusterstate/clusterstate_test.go b/cluster-autoscaler/clusterstate/clusterstate_test.go
index d0147009f126..9ff4eea5006f 100644
--- a/cluster-autoscaler/clusterstate/clusterstate_test.go
+++ b/cluster-autoscaler/clusterstate/clusterstate_test.go
@@ -1064,3 +1064,319 @@ func newBackoff() backoff.Backoff {
 	return backoff.NewIdBasedExponentialBackoff(5*time.Minute, /*InitialNodeGroupBackoffDuration*/
 		30*time.Minute /*MaxNodeGroupBackoffDuration*/, 3*time.Hour /*NodeGroupBackoffResetTimeout*/)
 }
+
+func TestUpdateAcceptableRanges(t *testing.T) {
+	testCases := []struct {
+		name string
+
+		targetSizes      map[string]int
+		readiness        map[string]Readiness
+		scaleUpRequests  map[string]*ScaleUpRequest
+		scaledDownGroups []string
+
+		wantAcceptableRanges map[string]AcceptableRange
+	}{
+		{
+			name: "No scale-ups/scale-downs",
+			targetSizes: map[string]int{
+				"ng1": 10,
+				"ng2": 20,
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Ready: make([]string, 10)},
+				"ng2": {Ready: make([]string, 20)},
+			},
+			wantAcceptableRanges: map[string]AcceptableRange{
+				"ng1": {MinNodes: 10, MaxNodes: 10, CurrentTarget: 10},
+				"ng2": {MinNodes: 20, MaxNodes: 20, CurrentTarget: 20},
+			},
+		},
+		{
+			name: "Ongoing scale-ups",
+			targetSizes: map[string]int{
+				"ng1": 10,
+				"ng2": 20,
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Ready: make([]string, 10)},
+				"ng2": {Ready: make([]string, 20)},
+			},
+			scaleUpRequests: map[string]*ScaleUpRequest{
+				"ng1": {Increase: 3},
+				"ng2": {Increase: 5},
+			},
+			wantAcceptableRanges: map[string]AcceptableRange{
+				"ng1": {MinNodes: 7, MaxNodes: 10, CurrentTarget: 10},
+				"ng2": {MinNodes: 15, MaxNodes: 20, CurrentTarget: 20},
+			},
+		},
+		{
+			name: "Ongoing scale-downs",
+			targetSizes: map[string]int{
+				"ng1": 10,
+				"ng2": 20,
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Ready: make([]string, 10)},
+				"ng2": {Ready: make([]string, 20)},
+			},
+			scaledDownGroups: []string{"ng1", "ng1", "ng2", "ng2", "ng2"},
+			wantAcceptableRanges: map[string]AcceptableRange{
+				"ng1": {MinNodes: 10, MaxNodes: 12, CurrentTarget: 10},
+				"ng2": {MinNodes: 20, MaxNodes: 23, CurrentTarget: 20},
+			},
+		},
+		{
+			name: "Some short unregistered nodes",
+			targetSizes: map[string]int{
+				"ng1": 10,
+				"ng2": 20,
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Ready: make([]string, 8), Unregistered: make([]string, 2)},
+				"ng2": {Ready: make([]string, 17), Unregistered: make([]string, 3)},
+			},
+			wantAcceptableRanges: map[string]AcceptableRange{
+				"ng1": {MinNodes: 10, MaxNodes: 10, CurrentTarget: 10},
+				"ng2": {MinNodes: 20, MaxNodes: 20, CurrentTarget: 20},
+			},
+		},
+		{
+			name: "Some long unregistered nodes",
+			targetSizes: map[string]int{
+				"ng1": 10,
+				"ng2": 20,
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Ready: make([]string, 8), LongUnregistered: make([]string, 2)},
+				"ng2": {Ready: make([]string, 17), LongUnregistered: make([]string, 3)},
+			},
+			wantAcceptableRanges: map[string]AcceptableRange{
+				"ng1": {MinNodes: 8, MaxNodes: 10, CurrentTarget: 10},
+				"ng2": {MinNodes: 17, MaxNodes: 20, CurrentTarget: 20},
+			},
+		},
+		{
+			name: "Everything together",
+			targetSizes: map[string]int{
+				"ng1": 10,
+				"ng2": 20,
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Ready: make([]string, 8), Unregistered: make([]string, 1), LongUnregistered: make([]string, 2)},
+				"ng2": {Ready: make([]string, 17), Unregistered: make([]string, 3), LongUnregistered: make([]string, 4)},
+			},
+			scaleUpRequests: map[string]*ScaleUpRequest{
+				"ng1": {Increase: 3},
+				"ng2": {Increase: 5},
+			},
+			scaledDownGroups: []string{"ng1", "ng1", "ng2", "ng2", "ng2"},
+			wantAcceptableRanges: map[string]AcceptableRange{
+				"ng1": {MinNodes: 5, MaxNodes: 12, CurrentTarget: 10},
+				"ng2": {MinNodes: 11, MaxNodes: 23, CurrentTarget: 20},
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			provider := testprovider.NewTestCloudProvider(nil, nil)
+			for nodeGroupName, targetSize := range tc.targetSizes {
+				provider.AddNodeGroup(nodeGroupName, 0, 1000, targetSize)
+			}
+			var scaleDownRequests []*ScaleDownRequest
+			for _, nodeGroupName := range tc.scaledDownGroups {
+				scaleDownRequests = append(scaleDownRequests, &ScaleDownRequest{
+					NodeGroup: provider.GetNodeGroup(nodeGroupName),
+				})
+			}
+
+			clusterState := &ClusterStateRegistry{
+				cloudProvider:         provider,
+				perNodeGroupReadiness: tc.readiness,
+				scaleUpRequests:       tc.scaleUpRequests,
+				scaleDownRequests:     scaleDownRequests,
+			}
+
+			clusterState.updateAcceptableRanges(tc.targetSizes)
+			assert.Equal(t, tc.wantAcceptableRanges, clusterState.acceptableRanges)
+		})
+	}
+}
+
+func TestUpdateIncorrectNodeGroupSizes(t *testing.T) {
+	timeNow := time.Now()
+	testCases := []struct {
+		name string
+
+		acceptableRanges map[string]AcceptableRange
+		readiness        map[string]Readiness
+		incorrectSizes   map[string]IncorrectNodeGroupSize
+
+		wantIncorrectSizes map[string]IncorrectNodeGroupSize
+	}{
+		{
+			name: "node groups with correct sizes",
+			acceptableRanges: map[string]AcceptableRange{
+				"ng1": {CurrentTarget: 10},
+				"ng2": {CurrentTarget: 20},
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Registered: make([]string, 10)},
+				"ng2": {Registered: make([]string, 20)},
+			},
+			incorrectSizes:     map[string]IncorrectNodeGroupSize{},
+			wantIncorrectSizes: map[string]IncorrectNodeGroupSize{},
+		},
+		{
+			name: "node groups with correct sizes after not being correct sized",
+			acceptableRanges: map[string]AcceptableRange{
+				"ng1": {CurrentTarget: 10},
+				"ng2": {CurrentTarget: 20},
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Registered: make([]string, 10)},
+				"ng2": {Registered: make([]string, 20)},
+			},
+			incorrectSizes: map[string]IncorrectNodeGroupSize{
+				"ng1": {CurrentSize: 8, ExpectedSize: 10, FirstObserved: timeNow.Add(-time.Hour)},
+				"ng2": {CurrentSize: 15, ExpectedSize: 20, FirstObserved: timeNow.Add(-time.Minute)},
+			},
+			wantIncorrectSizes: map[string]IncorrectNodeGroupSize{},
+		},
+		{
+			name: "node groups below the target size",
+			acceptableRanges: map[string]AcceptableRange{
+				"ng1": {CurrentTarget: 10},
+				"ng2": {CurrentTarget: 20},
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Registered: make([]string, 8)},
+				"ng2": {Registered: make([]string, 15)},
+			},
+			incorrectSizes: map[string]IncorrectNodeGroupSize{},
+			wantIncorrectSizes: map[string]IncorrectNodeGroupSize{
+				"ng1": {CurrentSize: 8, ExpectedSize: 10, FirstObserved: timeNow},
+				"ng2": {CurrentSize: 15, ExpectedSize: 20, FirstObserved: timeNow},
+			},
+		},
+		{
+			name: "node groups above the target size",
+			acceptableRanges: map[string]AcceptableRange{
+				"ng1": {CurrentTarget: 10},
+				"ng2": {CurrentTarget: 20},
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Registered: make([]string, 12)},
+				"ng2": {Registered: make([]string, 25)},
+			},
+			incorrectSizes: map[string]IncorrectNodeGroupSize{},
+			wantIncorrectSizes: map[string]IncorrectNodeGroupSize{
+				"ng1": {CurrentSize: 12, ExpectedSize: 10, FirstObserved: timeNow},
+				"ng2": {CurrentSize: 25, ExpectedSize: 20, FirstObserved: timeNow},
+			},
+		},
+		{
+			name: "node groups below the target size with changed delta",
+			acceptableRanges: map[string]AcceptableRange{
+				"ng1": {CurrentTarget: 10},
+				"ng2": {CurrentTarget: 20},
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Registered: make([]string, 8)},
+				"ng2": {Registered: make([]string, 15)},
+			},
+			incorrectSizes: map[string]IncorrectNodeGroupSize{
+				"ng1": {CurrentSize: 7, ExpectedSize: 10, FirstObserved: timeNow.Add(-time.Hour)},
+				"ng2": {CurrentSize: 14, ExpectedSize: 20, FirstObserved: timeNow.Add(-time.Minute)},
+			},
+			wantIncorrectSizes: map[string]IncorrectNodeGroupSize{
+				"ng1": {CurrentSize: 8, ExpectedSize: 10, FirstObserved: timeNow},
+				"ng2": {CurrentSize: 15, ExpectedSize: 20, FirstObserved: timeNow},
+			},
+		},
+		{
+			name: "node groups below the target size with the same delta",
+			acceptableRanges: map[string]AcceptableRange{
+				"ng1": {CurrentTarget: 10},
+				"ng2": {CurrentTarget: 20},
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Registered: make([]string, 8)},
+				"ng2": {Registered: make([]string, 15)},
+			},
+			incorrectSizes: map[string]IncorrectNodeGroupSize{
+				"ng1": {CurrentSize: 8, ExpectedSize: 10, FirstObserved: timeNow.Add(-time.Hour)},
+				"ng2": {CurrentSize: 15, ExpectedSize: 20, FirstObserved: timeNow.Add(-time.Minute)},
+			},
+			wantIncorrectSizes: map[string]IncorrectNodeGroupSize{
+				"ng1": {CurrentSize: 8, ExpectedSize: 10, FirstObserved: timeNow.Add(-time.Hour)},
+				"ng2": {CurrentSize: 15, ExpectedSize: 20, FirstObserved: timeNow.Add(-time.Minute)},
+			},
+		},
+		{
+			name: "node groups below the target size with short unregistered nodes",
+			acceptableRanges: map[string]AcceptableRange{
+				"ng1": {CurrentTarget: 10},
+				"ng2": {CurrentTarget: 20},
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Registered: make([]string, 8), Unregistered: make([]string, 2)},
+				"ng2": {Registered: make([]string, 15), Unregistered: make([]string, 3)},
+			},
+			incorrectSizes: map[string]IncorrectNodeGroupSize{},
+			wantIncorrectSizes: map[string]IncorrectNodeGroupSize{
+				"ng2": {CurrentSize: 15, ExpectedSize: 20, FirstObserved: timeNow},
+			},
+		},
+		{
+			name: "node groups below the target size with long unregistered nodes",
+			acceptableRanges: map[string]AcceptableRange{
+				"ng1": {CurrentTarget: 10},
+				"ng2": {CurrentTarget: 20},
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Registered: make([]string, 8), LongUnregistered: make([]string, 2)},
+				"ng2": {Registered: make([]string, 15), LongUnregistered: make([]string, 3)},
+			},
+			incorrectSizes: map[string]IncorrectNodeGroupSize{},
+			wantIncorrectSizes: map[string]IncorrectNodeGroupSize{
+				"ng2": {CurrentSize: 15, ExpectedSize: 20, FirstObserved: timeNow},
+			},
+		},
+		{
+			name: "node groups below the target size with various unregistered nodes",
+			acceptableRanges: map[string]AcceptableRange{
+				"ng1": {CurrentTarget: 10},
+				"ng2": {CurrentTarget: 20},
+			},
+			readiness: map[string]Readiness{
+				"ng1": {Registered: make([]string, 8), Unregistered: make([]string, 1), LongUnregistered: make([]string, 1)},
+				"ng2": {Registered: make([]string, 15), Unregistered: make([]string, 2), LongUnregistered: make([]string, 2)},
+			},
+			incorrectSizes: map[string]IncorrectNodeGroupSize{},
+			wantIncorrectSizes: map[string]IncorrectNodeGroupSize{
+				"ng2": {CurrentSize: 15, ExpectedSize: 20, FirstObserved: timeNow},
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			provider := testprovider.NewTestCloudProvider(nil, nil)
+			for nodeGroupName, acceptableRange := range tc.acceptableRanges {
+				provider.AddNodeGroup(nodeGroupName, 0, 1000, acceptableRange.CurrentTarget)
+			}
+
+			clusterState := &ClusterStateRegistry{
+				cloudProvider:           provider,
+				acceptableRanges:        tc.acceptableRanges,
+				perNodeGroupReadiness:   tc.readiness,
+				incorrectNodeGroupSizes: tc.incorrectSizes,
+			}
+
+			clusterState.updateIncorrectNodeGroupSizes(timeNow)
+			assert.Equal(t, tc.wantIncorrectSizes, clusterState.incorrectNodeGroupSizes)
+		})
+	}
+}