I have report of a Sig P220 and P220 Elite which had a failures to fire, and the owner reported he was not able to cycle the slide during remedial action. He declares he had to drop the mag to cycle the action.
This a Sig thing? They exhibit a reluctance to cycle in certain situations? I don't own one so I dunno.
(eta: I just thought it could've been an ammo issue, presume not at the moment)