SEO Trouble

[Anonymous]

I've used seo's many times with no problems, hiding the operators ect.
Now:
Trying a test: Subtraction of one roof piece from other main roof.

All walls have same ref line direction (on outside).
All roofs are the same, set with polyroof.
(Both the main roof (target) and the one I'm using as a operator).

As I SEO the section of roof I want gone with the operator,(all roof sections at once), on most of the target roofs it works, but others roof sections it does not.
Repeated SEO attempts do nothing to sections of roofs that failed and;

Have deleted all roofs and walls and started over to no avail.
Started a completely new .pln from AC 12 default template with all new test walls and roofs to no avail.
Built a different shaped test building and same scenario occurs over and over.

As in the image, the seo seems to have the most trouble with any two roofs that have an inside corner, or in other test building a recessed alcove which of course had three roofs that made up the alcove and neither of the three which made up two inside corners touching did the seo work.
What could be going on?

Edited; CONFIRMED; Only does NOT work when two roofs meet at inside corner. See next post with completely new file and test building which SEO FAILED.
lec

ps Image of SEO dialog does not reflect all operators and all roofs as explained above, just how it was when I did screen capture.

[Erika Epstein]

Actually, I don't recall seeing this behavior before. I've SEO'd poly roofs on L shaped buildings for years without seeing this behavior.

Some kind of bug as it is reproducible?