diff --git a/Sources/Private/CoreAnimation/Animations/RectangleAnimation.swift b/Sources/Private/CoreAnimation/Animations/RectangleAnimation.swift
index 00420f6149..13379947bc 100644
--- a/Sources/Private/CoreAnimation/Animations/RectangleAnimation.swift
+++ b/Sources/Private/CoreAnimation/Animations/RectangleAnimation.swift
@@ -9,12 +9,17 @@ extension CAShapeLayer {
   func addAnimations(
     for rectangle: Rectangle,
     context: LayerAnimationContext,
-    pathMultiplier: PathMultiplier)
+    pathMultiplier: PathMultiplier,
+    roundedCorners: RoundedCorners?)
     throws
   {
+    let combinedKeyframes = try rectangle.combinedKeyframes(
+      context: context,
+      roundedCorners: roundedCorners)
+
     try addAnimation(
       for: .path,
-      keyframes: try rectangle.combinedKeyframes(context: context).keyframes,
+      keyframes: combinedKeyframes.keyframes,
       value: { keyframe in
         BezierPath.rectangle(
           position: keyframe.position.pointValue,
@@ -37,7 +42,12 @@ extension Rectangle {
   }
 
   /// Creates a single array of animatable keyframes from the separate arrays of keyframes in this Rectangle
-  func combinedKeyframes(context: LayerAnimationContext) throws-> KeyframeGroup<Rectangle.Keyframe> {
+  func combinedKeyframes(
+    context: LayerAnimationContext,
+    roundedCorners: RoundedCorners?) throws
+    -> KeyframeGroup<Rectangle.Keyframe>
+  {
+    let cornerRadius = roundedCorners?.radius ?? cornerRadius
     let combinedKeyframes = Keyframes.combinedIfPossible(
       size, position, cornerRadius,
       makeCombinedResult: Rectangle.Keyframe.init)
diff --git a/Sources/Private/CoreAnimation/Animations/ShapeAnimation.swift b/Sources/Private/CoreAnimation/Animations/ShapeAnimation.swift
index 9c0175e017..945eebe33e 100644
--- a/Sources/Private/CoreAnimation/Animations/ShapeAnimation.swift
+++ b/Sources/Private/CoreAnimation/Animations/ShapeAnimation.swift
@@ -12,12 +12,6 @@ extension CAShapeLayer {
     pathMultiplier: PathMultiplier,
     roundedCorners: RoundedCorners?) throws
   {
-    if roundedCorners != nil {
-      try context.compatibilityAssert(shape is Shape, """
-        Rounded corners support is currently only implemented for Shape items
-        """)
-    }
-
     switch shape {
     case let customShape as Shape:
       try addAnimations(
@@ -28,15 +22,25 @@ extension CAShapeLayer {
 
     case let combinedShape as CombinedShapeItem:
       try addAnimations(for: combinedShape, context: context, pathMultiplier: pathMultiplier)
+      try context.compatibilityAssert(roundedCorners == nil, """
+        Rounded corners support is not currently implemented for combined shape items
+        """)
 
     case let ellipse as Ellipse:
       try addAnimations(for: ellipse, context: context, pathMultiplier: pathMultiplier)
 
     case let rectangle as Rectangle:
-      try addAnimations(for: rectangle, context: context, pathMultiplier: pathMultiplier)
+      try addAnimations(
+        for: rectangle,
+        context: context,
+        pathMultiplier: pathMultiplier,
+        roundedCorners: roundedCorners)
 
     case let star as Star:
       try addAnimations(for: star, context: context, pathMultiplier: pathMultiplier)
+      try context.compatibilityAssert(roundedCorners == nil, """
+        Rounded corners support is currently not implemented for polygon items
+        """)
 
     default:
       // None of the other `ShapeItem` subclasses draw a `path`
diff --git a/Sources/Private/CoreAnimation/Extensions/KeyframeGroup+exactlyOneKeyframe.swift b/Sources/Private/CoreAnimation/Extensions/KeyframeGroup+exactlyOneKeyframe.swift
index 4730913ab6..d20dc2d10f 100644
--- a/Sources/Private/CoreAnimation/Extensions/KeyframeGroup+exactlyOneKeyframe.swift
+++ b/Sources/Private/CoreAnimation/Extensions/KeyframeGroup+exactlyOneKeyframe.swift
@@ -17,6 +17,10 @@ extension KeyframeGroup {
   ///  - In those sorts of cases, we currently choose one one `KeyframeGroup` to provide the
   ///    timing information, and disallow simultaneous animations on the other properties.
   ///
+  ///  - We could support animating all of the values simultaneously if we manually
+  ///    interpolated the property for each individual frame, like we do in
+  ///     `CombinedShapeItem.manuallyInterpolating` and `BezierPathKeyframe.combining`
+  ///
   func exactlyOneKeyframe(
     context: CompatibilityTrackerProviding,
     description: String,