As a warrior - unconfirmed on other classes.
If I have max rank on all my learned through talent spells such as mortal strike or bloodthrist (31 point talents), if I change from arms to prot and then bac to arms I lose my max rank spells and they are reverted to rank 1. This only affects abilities learned through talents.
If other classes could confirm that would be great. I have reported the bug. Found out today after doing bgs all day with rank 1 abilities.

