IP Display error?

So for the past few months I've noticed my IP Fluctuating, sometimes it'll say I have enough to buy a champion I want for example, then when i go to buy it, Not enough. Right now it says I'm sitting at a comfy 6550 IP however I cannot buy anything priced at 6300 so Im a little confused. I'm curious if this is a new bug or not, let me know if your experiencing this and or how to potentially fix it. Thanks.