mac os x, Version 8 (8.16.25028.13002, 2025-01-28)
I have a cylinder with some details on the upper part (left)
Subselection + gumball (solid-Editing) will exend the cylindric surface with unnecessary, additional Knots (seen in the additional isocurves)
the result is the same wether I edit the upper part with details, or just the planar bottom surface.
solidEdit_knot_massacre.3dm (3.8 MB)
kind regards -tom