Most perplexing.....you may have to remove the grip and check your detent spring. If this is not in the lower correctly, it may get stuck in a position. I also have to wonder if you did not lose a counter spring in your trigger assembly.
Another thing is, did you get a piece of something between your trigger and the fire selector?
"Who are the militia? Are they not ourselves. Congress have no power to disarm the militia. Their swords, and every other terrible implement of the soldier, are the birth-right of an American...(T)he unlimited power of the sword is not in the hands of either the federal or state governments, but, where I trust in God it will ever remain, in the hands of the people." (Tench Coxe, Freeman's Journal, 20 Feb 1778)