Inconsistent 'Emissary of War' Quest Rewards Season 1

Haven’t been able to find a similar post about this yet, and I was hoping to have some input from anyone else noticing this.

I’ve done the ‘Emissary of War’ quest this week for the Dungeon Bonus event on three characters. The reward detailed in the quest is a Heroic 610 gear chest. On two characters I received a 619, and one I got a 626. Meanwhile, my friend who did all the same dungeons with me was stuck with a 613.

Not a super big deal in the long run but the inconsistencies are interesting, and there doesn’t seem to be ANY detail whatsoever on the reasoning for this. It didn’t seem to be based on the dungeon type (all Heroic v. Mythic) since I got 619 for both.

Curious if anyone else has experienced this. Thanks!