Part Transparency bug

I've updated to solidworks 2021 and a bug appeared.

If part A is behind part B, and part B is set to transparant, it renders part A also transparant, although it is NOT set to transparant. I've added 2 photo's for clearance (part A is the ball, and part B is the square box)

If I rebuild, or save the file, it renders proberly for a second, but after I do a single action (move the camera, or touch something) part A becomes transparant immidiately again. 

Looked at all my settings (mainly the setting "assembly transparency for in context edit" doesn't fix it) and checked 100 times to make sure part A isn't set to transparant.

Anyone knows a fix for this?

SolidworksModeling And Assemblies