helpfully overwriting rune pages

this bug occurs every game. it does not occur for my friends. I tried to uninstall/reinstall and that stopped the behavior for 2-3 games then it began again. It has been going on since snowdown. I reported it once from the game end screen, I think during 9.1

at every game start in every game mode my third rune page is replaced with one titled "Blitz: " . It is pre-filled with a decent set of runes for that champ, which often vary slightly or wildly from what I want.. If I reroll or change champs, the runes change, along with the name. Note that summoner spells also change each time.

(Note I am unsure whether the Blitz is a reference to Nexus Blitz, I only played that mode 2 or 3 times.

If I go to collection->runes and move my third rune page to another position, at next game start it is yanked back to third position and the changes go on.

I'm a computer programmer by trade. There is nothing I hate more than a computer that thinks it knows better than me what I want.

Please make this stop!