I don't think that exp elixirs are working correctly?

[Rare]

Im on level 30 mage, the problem occurred yesterday when i got 1 hr elixirs, my other hero warrior level 31 didnt get this problem last time while leveling up

Hmmmm. I capped my sorcerer lay night. 7 day elixir and 2x elixir netted around 850 xp on a group of 4.