Welcome to the Bersa Pistol Forum from The Lone Star State.
On your problem, does it happen when you fire the BT380 SA or DA or does it make a difference??? Is it a new gun or is well used. When do you let the hammer down with the De-cocker?? What I mean is do you insert a full mag in the BT380 with the safety off, then rack the slide to chamber a round which will leave the hammer in the ready or full back position...??