Sapience quoted in a recent thread:

"This change will be live as part of Update 11 on Monday May 13th.

They are just ending something that people have been working years on.
Oddly enough this is exactly why it's being changed. It was never intended that any of these deeds take years. In fact this has been bugged a number of times by players and was very much a bug in need of fixing. The idea that one class can complete these easily while another takes years is the very opposite of the intent.

That said, it should be clarified that you will not get credit for simply being in the group. We realize much of the perception of this change is that we're making it work like kills in PVE. Unlike the way kills are counted in PvE, where you just need to be in the group to share XP and loot, for PvMP you will need to have contributed during the fight in one of two ways.

Contribute damage within 20 seconds of the death of their target.
Affect the vitals of one who is already on the contribution list by healing their morale or restoring their power.
There is no "go AFK and farm deed credit" ability. No contribution means no credit."

peace out!