On my Gen 3 it’s a combination of the belt webbing folding over occasionally and getting stuck feeding into the upper redirection mount on the B pillar, and also the retractor spring weakening. A stronger retractor used to be able to just pull it on through, making the webbing straighten out on its own. I’ve had to just get into the habit of hand-positioning the belt as I take it off so it isn’t turned over, and also sometimes feeding it in a bit to get it started. Get in a hurry and neglect this, I’ve ended up accidentally having the buckle get closed in the door – which of course isn’t good for either the buckle or the door frame / door.
Seatbelts do have a lifetime warranty, but I think it has to be a safety-related thing to get a replacement (e.g. webbing worn too much, buckle won’t snap in, etc.), not just an inconvenience such as this.
