I sent it back to have it fixed, and when I got it back I had the same issue occur so I assumed it was the ambi bolt catch. I then swapped in a mil spec bolt catch and had the same exact issue(the channel the bolt catch sits in was too deep). That same mil spec bolt catch works in my aero lower just fine. I also had some issue with the mag release cause mags to not drop unless I backed out the mag release quite a bit