I found one thread-safety issue in chamferFilletPolygon() (due to its call to RemoveNullSegments()), but I think we only call that on the "owned" zone from each thread, so it shouldn't be the issue here (and indeed fixing it doesn't fix the bug.)
I found one thread-safety issue in chamferFilletPo lygon() (due to its call to RemoveNullSegme nts()), but I think we only call that on the "owned" zone from each thread, so it shouldn't be the issue here (and indeed fixing it doesn't fix the bug.)