Extra CDR shown after recalling to base

I just recently played a bot game where my HUD showed that I had 10% extra CDR than what I actually had. It showed I had 30%, but the items I had only added up to 20%, and I was not running any extra CDR runes or masteries. The skills displayed the cool down scaled to 30% instead of 20% as well. This only happens when I leave base after recalling, but I don't think it happens all the time.