Nice backup site but its loose - Texas Weapon Systems Gen-3 Basic Rear Peep Sight for Gen-3 Top Cover

I've attached this to my Texas weapon dust cover but it's not secure. It's loose when the screw is fully sealed. I don't know if it's a defect. But you cannot retain zero with this at all. The quality of the product is solid but it does me no good if its not still, tight and useable. I'd recommend but I seem to not be the only one with this issue.