"Unsupported type EventReference" error when saving prefabs with Timeline in Unity Editor

I’m encountering an editor-only console error when viewing and saving prefabs that contain Unity Timeline tracks with FMOD event playables:

Unsupported type EventReference
UnityEditor.EditorApplication:Internal_CallGlobalEventHandler ()

Environment:

  • Unity Version: 6000.2.10f1

  • FMOD Unity Integration Version: 2.03.09

  • Platform: macOS

When it occurs:
The error appears specifically when:

  1. Opening a prefab in the Unity Editor that contains Timeline tracks

  2. Saving changes to these prefabs

  3. The Timeline contains FMODEventPlayable assets

Technical details:
The error seems to occur when Unity’s serialization system encounters the EventReference struct. The struct is properly marked with [Serializable] and works correctly at runtime, but Unity’s Timeline serialization path appears to have issues with the custom type.

Looking at the code, EventReference is used in:

  • FMODEventPlayable.EventReference (line 27 of FMODEventPlayable.cs)

  • FMODEventPlayableBehavior.EventReference (line 189 of FMODEventPlayable.cs)

Impact:

  • This appears to be an editor-only warning

  • Audio events seem to function correctly at runtime

  • Prefab changes are saved successfully

  • No actual functionality appears to be broken

Question:
Is this a known issue with Unity’s Timeline system and the EventReference type? Is there a recommended workaround or will this be addressed in a future FMOD integration update?

This is a Unity serialization bug.

I’d just like to confirm that this is no longer an issue for you, as it appears to be an issue with Unity’s serialization?

Yep, it’s Unity’s bug. Thanks for checking in.

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