The function XenForo_Model_InlineMod_Thread::moveThreads process each thread, and sends an alert to the user (if needed). One of the parameters of the alert function is $thread. What I've noticed is that $thread is being transferred to XenForo_Model_Thread::sendModeratorActionAlert when it still holds its old node id. I think it should hold the new one, since the thread being saved (`$dw->save()`) and only then the alert being sent. So at this point the thread already has been moved, and the node id should be updated.