If you have a different BSP issue that is unrelated to the report made and provided, we ask that you create a new AnsweHub post for tracking purposes.
What do you exactly mean by “stacked” BSPs
In this particular report for the repro steps the user provided an example of additive box brushes duplicated and stacked on one another. This made it so the multiple brushes acted as one single face after building the geometry and lighting.
Thank you,