bump ive had this happen to me too!!! plz fix

If you edit your mastery pages after choosing the one you want, you can usually get the right page. What I find is that when I try to edit masteries in this way, instead of editing the mastery page I have currently chosen (A in the example), it'll start up editing the one I had before (B in the example). Switching to A usually solves the problem.

But this is still a bad problem to have in game.

Yeah, it is fairly common.

Similar thing happens when you do the following with RUNE PAGES (CUSTOM):

if you are in custom (i play ARAM a lot) and while you wait for all 10 summoners, say you view another summoner's profile, go to their rune pages click each (let the game start as you are looking at the other summoners rune pages) the screen will force close what you are seeing but when you go to select YOUR rune pages the NAMES and STATS while in dropdown are that of the summoner you were viewing. When game starts, you dont use the rune page of that summoner, you use the RUNE PAGE that would have been in the same spot as the other summoners that you selected.

Could have worded that a tiny bit better, but once that game starts as you are looking at the other summoners rune pages and try to select one of your own in champion select you will know exactly what i mean.

I posted this bug and how to reproduce it several times and topped it for weeks and got no response... this has been going on for a very long time now...