Stop moving it so much. This more than anything stresses them to no end, especially leathers. Of the three photo's I see with the devil's hand in it, it's in a different location each time. It can sometimes take weeks for a leather/soft coral to acclimate again once moved.
Just on the off chance, how long has it been acting like this compared to adding the MH
? How was the tank acclimated to the new/increased light intensity?