> Ok,thanks, here's another one, the same situation

Yup, looks like the same or related issue - I undid the boolean by separating out the surface and untrimming them (selecting edges and hit delete), then re-booleaned it with the new tune-up in place, and it seems to fix this one as well (model attached).

This version had several little curly-cue loops around the edges - I have seen these in a couple of models but I didn't know what was causing them, it looks like they are another side effect of too loose edge tolerances.

It seems like this may be a pretty significant fix for the next beta.

- Michael