Union is going wrong

(I dont know if this is where i should post this)

This is. some weird behaviour unions are giving me (trying to make a corner hallway, but these weird flakes keep appearing.

Anyone know how to fix this? I’ve tried changing render fidelity and stuff but it keeps happening.

Making it so the union is not zed fighting.

When you don’t have them unions if they are flashing colors and materials then they are zed fighting.

You can fix this by making the part bigger than the other

Nothing is z-fighting when i union, its just once unioned which it starts. Nothing is flashing and all the scales are exact.