buying multiple Arcane Essence results into only one

[ǝʎǝpɐǝᗡ-soɐɥƆ]

Basically what the title says: I decided to spend my Mana Shards and bought 6 Arcane Essence. Clicked the 5x button once and the 1x button once. It did show me in the bottom left corner that I bought 6 essence but there were only 2 in my inventory.

Hope it helps and thanks for the awesome game!