I never have that problem but then I never crimp. I've seen it befor and it is the crimping part. If the bullet is caught on the edge of the mouth, what happens is that the neck buckles on one side and the case won't even go in the die all the way. Well maybe with enough leverage.
As to not crimpimg, I've never had trouble with bullets seating deeper on recoil, as least not noticeably. And if they have, hunting accuracy has never been adversely affected. Think I would crimp in a tube fed lever gun.