so i reported this on wow forums but thought you guys should know that i actually found why it wouldn't trigger the heal sometimes.
forum link:
http://forums.worldofwarcraft.com/th...22254623&sid=1
and screenshots to show:
http://dl.getdropbox.com/u/17207/ADfail1.JPG
http://dl.getdropbox.com/u/17207/ADfail2.JPG