When rotating the 3d view, it flips 180deg.
I can't reliably suss at which angle I rotate through to get it to flip, because it's either at different point, or I can't tell whether I'm looking at the correct orientation, or the flipped orientation!
I've got this problem with the current 5.5.11, but I've also seen this in several previous revisions.
This is also still a problem with the curret beta. It just flips back and forth as I'm attempting to retate.