It's actually the first game-breaking bug I encountered since 2016... nonetheless, I was playing the arena, attacked a team which had a Crusader Eddie, who used his fury twice in the battle.
After the immunity-to-all-damage from Crusader's fury ended, the droid still behaved as if he was immune to damage when his HP reached 0.
I guess could be connected to his passive, giving him endure when on the verge of death, but the effect was not shown in active buffs nor was it removable. Moreover, the "endure" would kick in even when "Perfect Corruption" was inflicted.
I managed to capture 3 minutes of my futile efforts on the video, so that it would be easier to recreate the situation.

(gameplay recorded on Galaxy S8+ in 720p)