With the slide back and inserting a full magazine till you hear a click then sharply tap the bottom of the magazine with the palm of you hand. Did the slide move forward chambering a round? Be sure your safety is on and the weapon is pointed in a safe direction.
This has been brought up many times at the bersa talk forums.
Bersa says it is designed to do that.
If you are in a tight spot and you have to change out magazines, all you have to do is drop the empty and slap a fresh one in and the slide automatically closes and loads the first round off the top.
At least that is the way it was explained.