OffsetSrf results undesirable - can cause problems

OffsetSrf in V6 produces undesirable results for smooth partially closed surfaces with two opposite edges coinciding including cylinders. The result of OffsetSrf is a polysurface comprised of two trimmed,overlapping surfaces, not a single untrimmed surface as in V5. The V5 results are clearly preferable to the V6 results. Polysurfaces comprised of trimmed, overlapping surfaces can cause problems if any further modeling is to be attempted with these polysurfaces.

Attached is a file with several examples with results from both V5 and V6. Offset Srf V6 Undesirable.3dm (143.1 KB)
V6 version (6.0.17129.11351, 5/9/2017)
UnrollSrf options Distance=5 Corner=Sharp Solid=No Loose=No Tolerance=0.001 BothSides=No
FlipAll used for all surfaces.

Thanks again for the sample file and report. I believe this one shows the same issue and I’ve added the file to