My buddy has a 3.5 inch gold and his had a tendency to jam by not extracting. He put an upgraded spring kit in it (available in cabelas for about $100) and it got even worse. He ended up putting the original stuff back in it.
However, while he had the stronger spring kit and mag spring, he noticed problems with the action not closing and had a similar problem to yours. I would say that it sounds like the mag release is not functioning. If you have had it completely apart and cleaned and it is still doing it, I would let Browning know.....they are really good about a problem like this......it is not the ordinary spent shell jam.
I just bought a gold 3" for my father and it works great.......my experience is the gold 3" is better on not jamming than the 3.5. Just my 2 cents. Good Luck