How to reproduce:
1. Open the attached project
2. Open and play AnimationEventError scene
3. Notice the error: "Failed to call AnimationEvent ...
The function must have either 0 or 1 parameters and the parameter can only be: string, float, int, enum, Object and AnimationEvent."

Note: While animation is playing it triggers event which uses user's created class as a parameter

Not reproducible: 5.1.4f1