Yep, as far as I know the Final Sting damage is an inverse function of its HP. That is, a full health bee will barely tickle you, but a low health bee will oneshot you.

It's fairly easy to deal with them once this happens. Burn the bees down as your priority every time you have a pull involving the bees (or if boss 1 summons them as adds). Then, when the bee gets lowish on health, or starts casting Final Sting -> Stun them. Be ready to use a paladin stun or warrior stun at about 10% health. DPS should be able to finish them off then.

The trick is to kill them fast once you start. Two bees flying around on full health isnt too bad, but the worst thing you can do is start dpsing them then change target or do something else. Stuns are your friend when on low health, and you need your DPS to be aware of how damaging the beestings are.