MergeAllFaces crash

Running MergeAllFaces on this polysurface crashes Rhino 7 (7.0.20049.13225, 2/18/2020)mergeallfaces crash 2.3dm (125.4 KB)

For me, it goes on forever without crashing. Maybe I didn’t wait long enough. I could repeat the problem with just two of the faces from your object.
https://mcneel.myjetbrains.com/youtrack/issue/RH-57219
Thanks for the report.