Engine crashing anytime i move or delete a BSP brush

I’ve been having the exact same crash. For me it happens whenever I resize a BSP, place any mesh from the modelling tools or even doing Ctrl Z on a postprocess volume. Still haven’t found a fix yet.
It all seems to work completely fine on another project I have locally, so I do wonder what has gone wrong. Another thing to note is that my teammates suffer the same crash too.