K2SO dies in 1 hit!?!? Why?

I have noticed, my K2SO dies in 1 hit about every 3rd or 4 match. It does. It matter who hits him, but only in Arena, Grand Arena or Team Wars. Is there it a bug or something I am missing in his kit? My K2 is gear 11, health and x2 tenacity mods, with protection primaries. 32k life and 38k protection..... he has been 1 hit killed while full health and protection by Storm Trooper, Old Ben, one of the clones, Vader, and a number of others.... often the attacker had no buffs at all. Once he was killed first shot on a new match.... what is up with this? I will try to catch it on video now.