Savage and Buff Immunity

So did he actually get the buff immunity too?

His special clears all debuffs on him when he gets crit so debuffs don't really help much on him.

Putting Buff immunity on him and critting at the same time could potentially clear the buff immunity as you are putting it on him.

Tfp is 1 of three that applies buff immunity before damage. As @Woodroward said crit will clear debuffs for Savage if his unique is zeted. so it probably went like this
1. Apply buff immunity
2. Damage crits
3. Buff immunity clears
4. Gains offense and defense up.

He wasn't zetad, and I do think he received buff immunity. I'll check next time I fight him