NRG: Update group peers if mismatched

Signed-off-by: Neil Twigg <neil@nats.io>

server/jetstream_cluster.go

@@ -2059,6 +2059,22 @@ retry:
 			goto retry
 		}
 		s.Debugf("JetStream cluster already has raft group %q assigned", rg.Name)
+		// Check and see if the group has the same peers. If not then we
+		// will update the known peers, which will send a peerstate if leader.
+		groupPeerIDs := append([]string{}, rg.Peers...)
+		var samePeers bool
+		if nodePeers := node.Peers(); len(rg.Peers) == len(nodePeers) {
+			nodePeerIDs := make([]string, 0, len(nodePeers))
+			for _, n := range nodePeers {
+				nodePeerIDs = append(nodePeerIDs, n.ID)
+			}
+			slices.Sort(groupPeerIDs)
+			slices.Sort(nodePeerIDs)
+			samePeers = slices.Equal(groupPeerIDs, nodePeerIDs)
+		}
+		if !samePeers {
+			node.UpdateKnownPeers(groupPeerIDs)
+		}
 		rg.node = node
 		js.mu.Unlock()
 		return nil