diff --git a/src/Avalonia.Animation/Animation.cs b/src/Avalonia.Animation/Animation.cs
index d15a9b78bb..3b4afa637a 100644
--- a/src/Avalonia.Animation/Animation.cs
+++ b/src/Avalonia.Animation/Animation.cs
@@ -105,8 +105,7 @@ namespace Avalonia.Animation
                         Property = setter.Property,
                         Cue = keyframe.Cue,
                         KeyTime = keyframe.KeyTime,
-                        timeSpanSet = keyframe.timeSpanSet,
-                        cueSet = keyframe.cueSet,
+                        TimingMode = keyframe.TimingMode,
                         Value = setter.Value
                     };
 
diff --git a/src/Avalonia.Animation/AnimatorKeyFrame.cs b/src/Avalonia.Animation/AnimatorKeyFrame.cs
index 02457cb9aa..74061d76db 100644
--- a/src/Avalonia.Animation/AnimatorKeyFrame.cs
+++ b/src/Avalonia.Animation/AnimatorKeyFrame.cs
@@ -16,7 +16,7 @@ namespace Avalonia.Animation
         public Type Handler;
         public Cue Cue;
         public TimeSpan KeyTime;
-        internal bool timeSpanSet, cueSet;
+        internal KeyFrameTimingMode TimingMode;
         public AvaloniaProperty Property;
         public object Value;
     }
diff --git a/src/Avalonia.Animation/AnimatorStateMachine`1.cs b/src/Avalonia.Animation/AnimatorStateMachine`1.cs
index 16d081d83d..1a51b897c0 100644
--- a/src/Avalonia.Animation/AnimatorStateMachine`1.cs
+++ b/src/Avalonia.Animation/AnimatorStateMachine`1.cs
@@ -246,6 +246,9 @@ namespace Avalonia.Animation
                         _targetObserver.OnCompleted();
                         handled = true;
                         break;
+                    default:
+                        handled = true;
+                        break;
                 }
             }
         }
diff --git a/src/Avalonia.Animation/Animator`1.cs b/src/Avalonia.Animation/Animator`1.cs
index 7036355ab4..dde69cbd65 100644
--- a/src/Avalonia.Animation/Animator`1.cs
+++ b/src/Avalonia.Animation/Animator`1.cs
@@ -19,7 +19,7 @@ namespace Avalonia.Animation
         /// <summary>
         /// List of type-converted keyframes.
         /// </summary>
-        private readonly IDictionary<double, (T, bool isNeutral)> _convertedKeyframes = new SortedDictionary<double, (T, bool)>();
+        private readonly SortedList<double, (T, bool isNeutral)> _convertedKeyframes = new SortedList<double, (T, bool)>();
 
         private bool _isVerfifiedAndConverted;
 
@@ -134,7 +134,7 @@ namespace Avalonia.Animation
 
                 Cue _normalizedCue = k.Cue;
 
-                if (k.timeSpanSet)
+                if (k.TimingMode == KeyFrameTimingMode.TimeSpan)
                 {
                     _normalizedCue = new Cue(k.KeyTime.Ticks / animation.Duration.Ticks);
                 }
diff --git a/src/Avalonia.Animation/Cue.cs b/src/Avalonia.Animation/Cue.cs
index fe36b13495..5a95c108e3 100644
--- a/src/Avalonia.Animation/Cue.cs
+++ b/src/Avalonia.Animation/Cue.cs
@@ -10,7 +10,7 @@ namespace Avalonia.Animation
     /// A Cue object for <see cref="KeyFrame"/>. 
     /// </summary>
     [TypeConverter(typeof(CueTypeConverter))]
-    public struct Cue : IEquatable<Cue>, IEquatable<double>
+    public readonly struct Cue : IEquatable<Cue>, IEquatable<double>
     {
         /// <summary>
         /// The normalized percent value, ranging from 0.0 to 1.0
diff --git a/src/Avalonia.Animation/KeyFrame.cs b/src/Avalonia.Animation/KeyFrame.cs
index 46be119c36..ea04aa0aab 100644
--- a/src/Avalonia.Animation/KeyFrame.cs
+++ b/src/Avalonia.Animation/KeyFrame.cs
@@ -7,6 +7,11 @@ using Avalonia.Collections;
 
 namespace Avalonia.Animation
 {
+    internal enum KeyFrameTimingMode
+    {
+        TimeSpan = 1,
+        Cue
+    }
 
     /// <summary>
     /// Stores data regarding a specific key
@@ -14,7 +19,6 @@ namespace Avalonia.Animation
     /// </summary>
     public class KeyFrame : AvaloniaList<IAnimationSetter>
     {
-        internal bool timeSpanSet, cueSet;
         private TimeSpan _ktimeSpan;
         private Cue _kCue;
 
@@ -30,6 +34,8 @@ namespace Avalonia.Animation
         {
         }
 
+        internal KeyFrameTimingMode TimingMode { get; private set; }
+
         /// <summary>
         /// Gets or sets the key time of this <see cref="KeyFrame"/>.
         /// </summary>
@@ -42,11 +48,11 @@ namespace Avalonia.Animation
             }
             set
             {
-                if (cueSet)
+                if (TimingMode == KeyFrameTimingMode.Cue)
                 {
                     throw new InvalidOperationException($"You can only set either {nameof(KeyTime)} or {nameof(Cue)}.");
                 }
-                timeSpanSet = true;
+                TimingMode = KeyFrameTimingMode.TimeSpan;
                 _ktimeSpan = value;
             }
         }
@@ -63,11 +69,11 @@ namespace Avalonia.Animation
             }
             set
             {
-                if (timeSpanSet)
+                if (TimingMode == KeyFrameTimingMode.TimeSpan)
                 {
                     throw new InvalidOperationException($"You can only set either {nameof(KeyTime)} or {nameof(Cue)}.");
                 }
-                cueSet = true;
+                TimingMode = KeyFrameTimingMode.Cue;
                 _kCue = value;
             }
         }