Apparently when rewarding the player for completion of the Monthly Challenge, the game scales the rewards down to whatever the effective player level is at the moment of completion.
In other words, your level 80 character can receive rewards scaled down to level 10 if you happened to “ding” the challenge in some starter area…
Pretty sure that’s not meant to be the case (because otherwise… say, what?!).
Seems like a slip-up in implementation – when calculating the reward, the current effective level is used instead of the maximum earned level.
Really, really frustrating.