I have tried in normal BGs as well in dungeons. It last worked when I was doing arenas Sunday. After I was finished doing them I ran a dungeon and used the spell on a boss. Nothing happened.
Yesterday I used it several times over the course of 3 BGs and not once did a single pet spawn when I hit the button. I even disabled add-ons for one of the fights (ouch).
Today in Silvershard mines I used it 2 times in one match and nothing occurred either time. I even tried to remove/reglyph my talents in case my minor glyph was bugged.
Couple this not working, along with some weird glitches with Heart of the Phoenix (pet rezzes but then despawns and when you go to resummon it tells you that pet is dead, yay), it makes for a very dead hunter.
Is this a known issue or am I just broken?