Last time out, my TRG42's trigger lost its 2 stage feature. What I mean by this is that it turned into a heavy single stage trigger, with the trigger locked solidly forward in the cocked position. While this was happening, the safety did not work. If I cycled the bolt a bunch of times, sometimes the 2 stage function would come back, but would be lost again after a few shots. Do I just have to adjust the trigger, or did something break?