So normally (from what I know), this is just a client-side error. Generally, our side shows the correct amount of IP and the maths going to the client gets lost in the void. Restarting your client usually fixes this issue.
However, if that doesn't fix it and your client is still showing the incorrect IP amount, you can shoot us a support ticket here :3
https://support.riotgames.com/hc/en-us/requests/new
On a separate note, try 45% CDR TF. You pick a gold card, like, every 2 seconds. It's fun. :3
: LUCKY THEM