When loading the project, and when jumping to different sequences when I use Animation Rigging in a timeline (specifically, when the RigBuilder component is enabled on a character), I get the following types of exceptions in the logs.
NullReferenceException: Object reference not set to an instance of an object

Repro:
- Open project, open sequences panel, go to Episodie 1 / Location 20 / Shot 50. Try to jump to Shot 60 and back to 50, watching the Console for exceptions such as the above.

notes:
- If you disable the RigBuilder component on "Ivy-v11-2 Prefab Variant" in the "Assets/_LOCAL/Episodes/Episode 1- Friendship Part 1/Episode 1 - Friendship Part 1.unity" scene (go into Ep1/Loc20/Shot50 - Ivy is in there). Re-enable the component the exceptions start coming again.
- I tried to create a new simple project using a small number of scripts etc, but it did not throw an exception. I deleted a lot of stuff from the project (it was 23GB!!!), so hopefully the uploaded files are sufficient to repeat the problem.
- If you jump around shots which do not have Rig Building enabled on characters, everything works well. As soon as you have a character with RigBuilder on, you get exceptions such as the above strack trace.