I run undercut analysis and nothing shown but occluded undercut - see att. image
did you try reversing the direction of the Top PLane selection?
Yes, I tried and nothing changed
OK, let's see a screen capture of the part geometry and feature manager tree. It would be helpful if you selected the top plane so that it highlights in the view.
it must have something to do with the setup in the options - some might be changed without my notice - I run the same part on diff. machine and had no problem - see below
Retrieving data ...