Not gaining credit for killing Poharan while dead

[Hinalover]

I've attempted Poharan 2 times today from 100% health. Both times I died sub 20%. By the time I res and run back into the arena the boss has little to no health. I got credit the first time to get the achievement, but the boss is not dropping the reward with the token needed to complete the daily. It appears the system is only registering the amount of time I damage the boss after I res as time committed to the boss and not the FULL amount of time spent on the boss. Given the extremely long respawn timer the boss has, this is an absolute pain in the rear end that I cannot complete this daily due to dying during the boss fight.