Wanna Change Your Masteries OH TO BAD!!!!

at the last 5 seconds oh look i have the wrong masteries u change it but what it stays the same masteries that you dont want oh man this happens all day every day to me, so when you try to change masteries or runes at last second think twice it wont work for some odd reason and ive experienced this numerous times so riot try to fix this glitch thank you.w