I've had it happen to both a frameless mask (after ~20 dives) and a framed one (after 200 dives). The lens didn't pull loose, the skirt pulled loose - and on one of the masks I still dove it about 5 times not knowing what the problem was and just clearing it more often. I finally discovered the problem in the pool, thinking it was leaking a bit.
The gap was 4" long. I'm amazed it wasn't instantly flooding.
The gap was 4" long. I'm amazed it wasn't instantly flooding.