There seems to be a bug where if you are group ported when you zone and disband you are unable to cast spells on yourself like Invis, Jboots, Levitation, etc. "You attempt to cast a spell on X but you are protected" or something along those lines. I've had this happen 5 times now and i think each time it happened I was ported from EC tunnel to Skyfire. Zoning fixes it, camping fixes it...and unfortunately finding out the hard way, dying fixes it.
I've seen this a few times porting into the new cobalt scar from guildhall. I wouldn't say it's exclusive to cobalt scar, its just the destination I most frequent in regards to casting a port spell. I was unable to invis self, speed buff, anything and saw the same error message that you quoted. Relogging fixed it. I figured it was some sort of desync with the client.
