Trigger problem

Having a problem with my newest AR-9 build, the trigger won’t reset if there is pressure on the trigger. If I let off the trigger I will lock back when charged but if I apply pressure and charge it the trigger just falls back to the fired position. Oddly enough though if I take the upper off and use my fingers to cock the hammer back it doesn’t matter whether I have pressure on the trigger or not, it will function properly. Super confused, wondering if it’s not my BCG.