Yes.. I'm a door card genius now!
With the window sitting loosely back on the winder its having trouble moving the window up (fast, slow, fast again) and after a few runs it jams again (needing another whack on the motor). Its odd that the mechanism seems to be squeaking as if something is sticking but that might just be the rubber seal.
I would have thought if the magnets come unbonded it would stop dead!
Mine did, but only after a few glitches of running slow, can't really be sure but it's possible, I think, that they were becoming loose before finally giving up all together. Or maybe some of the windings are shorting when the motor gets warm ?
It's annoying but I reckon that the only way to be sure is to change the thing, if it ISN'T the assy you could probably sell on again in the classifieds on here or eBay. I know it will cost a few quid
whatever you do but it has to be fixed.
As an aside the one window failure that really was a pain was in a a Toyota I had in Muscat, failed in the down position and it was nearly 50 degrees that day, the air con had no chance of cooling down Oman !
Good luck, let us know how you go.
EDIT. Mine still squeaks on the window seal, occasionally use a rubber/silicon spray and that cures it for a bit and then it has to be done again.