I'm having similar problems, especially with my clerics. It seems worse in DSK for some reason.
In DSK i'm having weird issues with the paladin spell Vengeful Retribution IV
webtools/spell.php?id=9061 If I cast it some times my cleric is fine and can still cast. Sometimes I get the grey spell bar after every cast (including clickies). Ducking fixes the grey bar, but next time I cast I still cant land a spell. I click off the buff icon and I can cast heals again. Then randomly during fights I have to duck and re-cast to try and heal same a original poster. It's been getting gradually worse over the last 2 weeks for me.
Not very enjoyable at the moment, instead of bashing my heal button, I have to actually look up at the clerics screen and ensure that the heal landed.
Also seems raid aura's are appearing in my normal spell icon slots that my toons dont have. I have 4 solo auras, and when I zone to DSK those spell icons appear as normal in the songs window, but sometimes I get raid auras in the normal spell window icons that I dont have. It varies which raid aura, but so far my tank seems to like having the aura of the deathbringer? (the raid ac one) buff icon in the normal gems spell icon, and the wizards seem to be grabbing the dmg raid aura proc (sorry forgot name). The only reason I notice it on the wizards the pet AA dosent stick (as the dmg is better from the buff).
Unsure if its related, but whatever is happening it's getting worse.