The only time I've seen similar issues is when there is a small piece of dirt/debris between the barrels and receiver. Good luck with this one.
I cleaned it up real well earlier and found some debris and it closed all the way but the throw lever still is not completely resetting.I am not familiar with the Rock Island guns, so take this FWIW. I do own a bunch of sxs shotguns though.
Clean everything up, oil it up good, and try again.
Does it have ejectors? If so try assembly with the forend off as maybe the ejector cocking mechanism is honked up.
That doesnt seem to be full lock up....but I have actually never had a side by side before....shouldnt the lever return to center?Thats normal
Ok, my concern was that it wasnt locked in enough to be safe to shoot.....learn something new everyday 🤷♂️🤷♂️Have a newish CZ that does that - their claim is that it is supposed to wear in. It is safe and secure on mine. Both old doubles the lever centers.