I have Clayton & Mills knickers that are stuck on 19/20 and have been for over a year. I have several pieces of apparel that don't improve, even when the sponsor box shows they should get points.
When opening the box it will show something like
Clayton & Mills Knickers 25/2 and it will make the sound indicating that the piece of apparel has levelled up, but the apparel in question hasn't increased in points as long as I can remember. I have several pieces of clothing that do this and it's frustrating to open a Gold Sponsor Box and see most of the points diverted to clothing that never increases in level or points.