A couple days ago, I went to a PuG raid to try to take down Doom Lord Kazzak. Tonight I tried to go into Gruul's with the guild and was unable to zone into the same raid as everyone else.
When I spoke to a GM about it, they said that it is a known bug that they are working on. Someone in the raid was in Gruul's beforehand and their RaidID got saved to me.
The GM suggested if you want to go into a WorldBoss situation or any other raid to ask around if they were in any other raids that you're looking at doing later in the week so you don't get saved by accident.
Never question the sanity of someone with the ability to spam moonfire.