
Pic1: Champ's awaken ability makes him immune to petrify, fate seal, and heal block.

Pic2: I didn't open mastery, Wills, and you can see Void's able to land petrify on Champ and caused Champ losing health which shouldn't happen at all.

Pic3: When I used 4r5 sig55 Void to fight with Champ, 2 stacks of petrify reversed Champs SP1 regeneration.

Pic4: If Champs is immune to petrify, Void shouldn't create Fear of Void since petrify cannot be landed on Champ.
From the facts above, It's no doubt that there's a huge bug of Champ's immune ability. I hope Kabam can fix up ASAP.