In Game Bug?

I don't have a screenshot as I did not think of doing it til after this most recent game, I've been having a problem in-game as I'm playing, I will have the gold for an item, (full build item such as dead man's plate, spirit visage, duskblade, luden's echo, etc.) and the buy option is grey, I cannot purchase by right clicking on the item, or left clicking and hitting purchase, it also doesn't update the prices 95% of the time til I click off the item and back onto it, this has happened in the last 5-6 matches I have played, I've tried restarting the client, I've tried leaving the game and rejoining, nothing works, how is this bug allowed to be in the game? Why should I or my team get losses due to the fact, there is a bug in the game, not letting me purchase full items? Please riot, find a way to patch this :D [slayer-jinx-unamused]