OK... this one is a little nutty so I apologize in advance.
I have WPMU Dev installed on 2 sites (at least, I used to). I had an active site (projectedesign.com) and an inactive site (on an access domain). Today I made the site on the access domain active (so now it's projectedesign.com).
Just recently when I tried to edit the site with the Builder it would look all kinds of crazy (screenshot attached). The only thing I can think of is that it has something to do with the access domain going live. But I'm not sure. Hoping someone smarter than me can give me a more educated opinion.