Several times whilst playing consecutive matches and switching masteries inbetween each match the masteries will stick to the previous one used regardless of it being switched.
Example my last match played as Rammus Jungle I use 0/21/9 though in game often it'll switch to my ad carry page 21/0/9 severely gimping me.
Most noticable when hitting tab and seeing 3% lifesteal that shouldn't be there and not having the 6 dot on minions.
I've asked a few of my friends and they said they've had this happen to them as well so it can't just be me.
Having the masteries not change inbetween matches is severely menacing for gameplay when you think you're running one way and end up goin another.
Happened to me as well.
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