Nanuq - Unfortunately, it does sound like you have a rep crown, but some good, clear macros (especially, of the internal components) would be very helpful.
Have you removed (unscrewed) the inner components to inspect the spring? Generally, when the crown feels like it is slipping during winding, it is because either the spring is worn (or collapsed) or the flats of the internal components have rounded - both, from what I have seen, are common problems on either aftermarket or very old gen crowns.