I've got the opposite problem. Doing the Undying Mind raid - others left at the start so I solo'ed all the first part, right up to, after climbing the high steps, the 'Kill Three Witches' - and then two team-mates joined. Got right into the final battle arena then had to afk to go and jettison a twelve pound shit. Wasn't away more than a couple of minutes and, when I got back, saw I was RTO'd for 'inactivity'. Crap.