I've come into this bug several times since the update, and a couple times before it as well, although I have a feeling that U46 made this bug show up more often. I had it happen today just before fighting a dragon in Southern Elsweyr. Before, it happened quite frequently inside the Infinite Archive. Everytime it happens, I notice that I don't get the Foresight buff on my bar, and all my healing skills are not discounted. To fix it, I need to switch zones or relog.
I have sadly no idea what is causing it, since it's very random. I do have a slight suspicion that it has something to do with my werewolf transformation, since that's the only common variable between all situations where the bug showed up.