My 1260s does or should I say did this tried all of the above, I'm sure back in 2018 dealer was replacing discs because of this, I've since fitted Brembo Ore discs but noticed it's started doing it again but very minimal.
Same for me, clean the bobbins and ensure they can move freely. I use a little trick of a bolt and some nuts, bolt through the bobbin and tightened up loosely enough for it to grip the bobbin then I use a spanner to help spin whilst I spray the bobbin with brake cleaner.
