Champion Item Shop Bug

Sometimes when I buy something from the shop it says I have purchased it, but its not in my inventory. For example lets say I bought a Tear of the Goddess, after I purchased it my gold would go down accordingly to the price and the game would say I bought it but it is not in my inventory. After about a few seconds the game give me my gold back and I was able to purchase the item again, this time actually giving me my item.

I have had this bug for almost two months now and whenever I ask other players about this bug they say they never had it.