Quoted:
I have a new 21 and put about 100 rounds in it. I am have a problem
about every 20 rounds I had a failure to reset  trigger,,,,did not notice it
the first time dropped the mag . Just thought the slide did not lock racked the slide
and a round went flying. Happened a few more times so I took it back to the dealer to have it checked
no answers...I own many glocks and have never seen this
anyone have this if so what was  the fix thanks