Hi Tutubana,
Unfortunately, this has been a problem with BSP geometry for a while that we want to improve in the future when we get around to revamping how the system works. There isn’t any set timeframe for when this would occur, though.
There are already several tickets logged in our system related to BSP that are all currently backlogged.
For best practice when using BSP it’s better to use more blocks that aren’t edited by extruding faces or significant editing of the vertices or having a lot of overlapping BSPs in an area. These types of issues seem to happen more when doing so.
-Tim