Hey Pascal, just reporting back - you pointed out the issue, so I mistakenly thought it was a bug. While working with a bunch of these curves, I did not zoom into all of them as I should have to figure that out, so thanks. Furthermore, the SelSelfIntersectingCrv command wasn’t working and now it does. The strange thing is that I actually found more self-intersections, which were being ignored by RegionDifference - anyway, things back to normal now. Thanks again.