Flipped Home - Cracks Appearing on Wall Corners - Cause for Concern or Normal?
I wouldn't call it "normal", unless you're talking about the quality of work to expect in a flipped house.  The cracks don't look as much structural as caused by an atrocious job of finishing the corner.  It's hard to tell from the posted pictures, but it looks like they ran a corner trowel over the joint without taping it and on top of a couple coats of paint.  Between that and likely painting it hurriedly (they didn't really even sand that much), the existing paint separated in the corner.  This should be relatively straight-forward to fix - scrape off all the loose material, and then properly tape (I'd use fiberglass), mud and sand the joint.