I have also had the same problem for years now, I have seen various "fixes" and tried them, editing html files and such, but nothing works. For instance in my shared bank I resized and relocated all bags so that the slots are larger since I have a 1920x1200 resolution on a large monitor, and bags 1-7 are fine, but bag 8 keeps moving back to it's own position, and with smaller slots. I think I changed mine to 40 or 44 pixels, tried both, but bag 8 is always 32 pixels I believe. This also happens on 3 of my non-shared bags, I believe it's usually 11, 12, and one other, maybe 8 or 9. Very irritating and I don't know if it's an SOE problem, Profit, or what. I even went so far as to go back to one of the default UIsettings from Profit, rebuild the complete UI to the way I wanted it, and all was fine for a week or two, then it migrated back to the same problem. Any ideas?
