Some saigas will also put a weird double shoulder on the brass, like an enfield rechambered for x54r. These don't hurt anything.
Case wall dents won't do nuthin' bad, might reduce accuracy a little on the next loading, but they won't have much effect. It is likely the cases are hitting the topcover on ejection. Get another topcover and cut the ejection port back and out of the way, the dents will probably go away and the brass will fly in a more rearwards path, making it easier to pick up.
Are you shooting boxer primed ammo? If not then reloading it will be a PITA for you.