Ok if I close out LR and open it back up again the problem is solved.
I've seen this - also on windows 7 64. The worst was when I was importing images and started rotating imported before the full import was complete and the previews generated. These never would correct themselves, had to delete from the catalog and re-import. I've also had them where they only rotate 45 deg in the grid but the full 90 deg in loupe (using dual monitors with grid on mon 2), closing LR and restarting usually fixes these.
Haven't found a solution. Did the display driver update. Not sure as of yet if it solved the problem or not.
