Shouldn’t this count as a micro edge?
microedge.3dm (75.4 KB)
The surfaces were generated by OffsetSrf with Solid=Yes and even with some adjustments that I thought would be enough, they still fail:
solidify.3dm (198.0 KB)
Now, the quick fix for me was to move the flat surface back 0.1mm, which didn’t produce any gaps, but still the result is not pretty:
This was meant to be a super quick thing for 3D print, but this wasted some time for me…