Still having issues with "Hello Nurse" unlock

So I’ve been having problems unlocking the “Hello Nurse” achievement since the Castle Map Pack was released… I just cannot for the life of me get this achievement.

I play on Daybreak, Outcast, or Perdition and use the Regeneration Field as stated on a teammate near death. I must have done this hundreds of times now. I have even tried throwing grenades at myself and recharging my shields, as stated in many guides. Thus, I am doing the correct actions on the correct maps.

I have deleted the Castle Map pack from my hard drive and reinstalled it. I have cleared my system’s cache. I have even tried on both of my Xbox 360s, therefor using two completely different systems.

I have unlocked other achievements in the game since I had problems with this one. It’s become quite aggravating. I know it was stated that 343i was “working on it” several months ago, but nothing has come up since.

So, have any of you had this problem and found some sort of work-around?

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