Trigger Dead, sometimes

[BobSandy]

Fired for the first time my DWM (1921) luger. Extremely accurate and fun. My first luger to own. Received as a gift from my son. However, sometimes during the middle of emptying a magazine, the trigger is inoperable. Pressure on trigger and nothing. I drop out the mag, re-insert, and re-apply pressure and than it fires. Any ideas??