I've been slowly working on the Beast of Fable quest chain as well as the Pandaria elemental one with at least 6 of the 10 beasts defeated in the Fable chain. As I was doing some rep stuff in Outlands and traveled from Blade's Edge to Netherstorm, I got "Beasts of Fable quest accepted!" and the quest popped up. I checked and the 6 beasts I'd done already were wiped away. :(

After I did the rep stuff in Netherstorm, I flew to Shadowmoon to do some rep stuff there as well. As I crossed from Terrokar to Shadowmoon, same thing happened only for the Pandaria elemental quest chain. Haven't started that one yet so it was no big deal but this is an annoying bug. :(