There's a 170+ page thread on the official forums. It's pretty terrible they went live with 3.2 before fixing this problem. There's no update other than "Soon". So meh. If I wasn't raiding 3 nights a week I'd probably kill off my accounts in frustration of not being able to instance. So far, it hasn't affected me too much in northrend, but anything in BC or Classic, don't even try it after noon.