There an explanation if you figured out the clues in my first response. There is a server limit on the number of DoTs that can affect bosses. I believe it is something like 60 and lower number to SEE your DoTs on the boss/mob. So if that server limitation is on bosses, I can imagine that the server can maybe calculate damage from only so many people. There was a mention it takes it from say the highest 51 people doing damage.

There is no configurable Alliance in Void Ark, and it's only 24 people just working in parties of 3 so it's a different beast because it was designed for that number. However, Diadem allows for 72. Guess what? Only 51 of you top DPS folks will count. This is especially worse if you come in a bit too late in hitting the mob.

This is damage based, not "tagging" or "aggro" many would like to believe otherwise.

The short of it is, if your DPS are doing poorly against others who can do much better rotations....whether due to competence or latency. You're not gonna get credit.