Mr Fantastic bugged?

I just opened 6 of the featured 5 star hero crystals today and pulled a Mr Fantastic. I took him up to rank 4 and have been trying him out in loads of content but I think his petrify is bugged. if you have despair plus the petrify it should reverse the healing but it isn't. if this isn't a bug I will be very unhappy as thus far in the game, all petrify have been able to reverse healing and nowhere did it state mr fantastic wouldn't be able to. also even if he can't reverse healing he isn't even properly preventing healing. I had 6 debuffs on namour in variant 4 quest 1, 2 of which were petrify(35% reduction). plus 60% reduction from 2 points in despair and Namour still healed.