Did it happen suddenly? Sounds like it could have become magnetised. Not expensive to fix, or you can even buy your own demagnetiser for a few quid.
I'm not sure. It has always been a bit fast but I kept put off getting it fixed as it was only about 10 minutes a week, but then it got way worse at some point.
@Polky started
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Did it happen suddenly? Sounds like it could have become magnetised. Not expensive to fix, or you can even buy your own demagnetiser for a few quid.