[Pre-game Lobby] Runes show one page in lobby, but game loads with another

I ended my League play last night playing Ashe, and equipped my Ashe runes. Earlier in the day I had played Lux.

Today, I was placed in Mid and picked Lux. I changed my summoner spells and looked at my runes. My Lux rune page was already selected. I thought that was so strange, as my last game was ADC, not Mid, so shouldn't it have my Ashe page? I thought maybe the client was smart enough to automatically suggest a rune page with the name of the champion I drafted. I remember looking at it three times and it said that it was on my "Lux" page. And so, I never clicked the rune page drop down at all.

As soon as I hit the loading screen I saw Fleetfoot was my keystone and immediately realized that the game had loaded my Ashe page. Sure enough, the abilities in-game matched my Ashe page.

In short, I believe somehow the lobby display might show you on a certain rune page, but you may not actually be on that rune page. As I would have expected, the game loaded with my most recently used rune page active. However, I am 100% certain that the lobby had my Lux page up. I have also confirmed that my Lux rune page has not changed.