I have isolated the issue.

It is the repeater regions. Something is conflicting with them while in combat. I have no idea how to figure out what is not working though.

In Combat:
Using the Repeater Region = No heals casted
Pressing Control or Shift Myself (over the repeater region) = Heal casted

Out of Combat:
Using the repeater region = Heals casted
Pressing Control or Shift = Heals casted

So it has to be something conflicting with the regions while in combat.