[Experimental] Players completely invisible, animations broken.

I don't know how to recreate this bug. I really don't. It just suddenly started happening on my map with no explanation. It's a huge problem and I hope it gets solved/fixed.

Potential Steps:

1. Experimental Mode
2. Install Addons??
3. It happens?? I think?? I have no idea.

I really hope this bug either gets fixed, or solved-- I really need help, because it's destroyed my world.