On three occasions I have started the Northrend Account wide Pet Battle Master quest only to have it reset.
First time after having beaten 2 NPCs and logged off only to come back on to find it removed from my quest log.
The second after a server restart - again removed from my quest log.
The third after changing zones from Dragonblight to Zul'Drak for a final fight - again removed from quest log.

Anyone else having this issue?

NB