Flashing Mastery Issue

Not really sure what to do with the boards but here is my issue.

Its happened since day one of leage (early season 5) and is happened on two different computers.

When ever i flash my mastery everything freezes. For 5-10 seconds. After the freeze then the mastery flashes and everything is back to normal. Anyone ever come across this? What's the fix? I've thought about uninstall and reinstall.