I don't know what shells you are running, but I had 2 shotguns that absolutely would not digest Fiochi steel shot. The one was a Benelli M1 Super 90 (only times it ever malfunctioned), and the other was a Remington 870 (same ammo) I would have to bang the butt on the ground to eject the fired shell.
I'd try some different shells and report back.
I took that case of steel back to where I bought it, we walked out the back door of gunshop, I showed them on my 2 guns and they gave me a new case of shells (same shells), and I never had another issue.