Hi all,

Working on a part with some semi-interesting geometry, using surfaces to get what I want. 42 features in, have 2 surfaces that intersect, and I want to trim one by the other. In this case, cutting out the area inside the "fence". 

So I do that, and it appears to work fine:

But, the next time I do a CTRL+Q force rebuild, this happens:

It's very repeatable. I can sit here and spam CTRL+Q and watch