Weird slicing issue, missing parts of the model

I’ve never seen this issue before. I started off with this model, which isn’t colored. So I went through in Bambu Studio and colored the model:

All seemed fine, done this dozens of times before. However, now when I slice the model and get it ready to print, parts of it is missing. (sliced without supports to be able to show the missing areas, but same thing with)

Any idea what could be causing this? I tried OrcaSlicer as well and it’s the same thing.

Try turning on Print Thin Walls.

Perfect! I thought I had tired that but that fixed it.