Skins On Sale Bug

So on Monday i bought Blood Moon Elise it charged me the full amount and wasn't too sure if it was actually a bug and then I tried it again today with Arclight Vel'koz (675 on sale 1350 Regular price). It charged me the full amount again but on my recent purchases it says it charged me the discounted price. This bug seems to occur when you click on the skin that's discounted in order to view it and then buying it.