Tweens and Armatures bugging after 40th frame

I use Adobe Animate, I am by no means "new" to how tweens and armatures work, and have used them consistently in lots of animations.  I know how they work and function, and generally prefer to use them.

However, I was creating a fun animation where Kratos is a stick figure- when out of the blue, every tween or armature started bugging out after the 40th frame. When I add a keyframe to either the motion, classic OR armature layers, they all bug out and go out of place after the 40th frame. I have created different scenes, copied and pasted into separate documents, turned layers into symbols and even tried to restart everything completely- nothing worked.

I have searched and searched and - as far as I know - I am the only one who has this problem. Help would be very much appreciated! I'll leave a google drive link to the document below, the problem has persisted on multiple computers so it should still appear for you- just add a framse after the armature, classic or motion tween layers and you'll see what I'm talking about! Please let me know what I can do, any suggestions are much appreciated!

https://drive.google.com/file/d/1qpZPojeBHcemjaoW5vlINLIsDvvpgrBc/view?usp=sharing