Hi Supagoat, thanks for posting the file to reproduce this - it looks like a bug in the surface splitting mechanism, the way straight sections loft works internally is that it builds a long surface that has kinks in it and then splits it up, it seems that one piece is not getting split as it should.

Tommorrow I will take a closer look into the splitting mechanism to see some more details about the bug and investigate what's involved in fixing it.

Thanks, - Michael