By sitting loaded, you are talking about long term storage in that condition?
Just have to make sure if it's sitting loaded, you make sure the bolt is open.
The top shell in the magazine usually deforms if pressed against the bottom of the bolt carrier causing a FT-Feed after the first round is fired.
It's also possible that some of what I had read was based on older designs. I do know they(saiga) were redesigning part of the rifle/shotgun because of the concerns I mentioned.