Just this afternoon... the slide locked back (with more still in the mag) and hasn't moved since. It ejected properly. The slide release isn't caught in any way. No bullet got jammed. The mag dropped free when I released it. The slide is aligned properly on the frame rails. It's just frozen. The last round it fired wasn't unusual in any way. It's just locked back and cannot be made to move. I'm at a loss. Perhaps this one will go back for the refund, but I still have an F. I wonder if I can trust that one? I'm left with a Glock 34 and a Bersa .22 for carry... not great. Anyone heard of a malfunction like this?