Short story: I was in Moonglade and LFG’d in LookingForGroup for Ashenvale Incursion. Some guy invited me so I clicked my ring to teleport to him. As the ring finished, he kicked me from the group (no idea why). A summon pop-up appeared for a microsecond then vanished and I was left in Moonglade with ring on cooldown, having to fly like a peon.
Lesson learned: make sure people in group are friendly before entering the “dream of a friend”.