[CLIENT] Wrong masteries to pick from after I saw someone elses masteries.

I was on the lobby of my client watching at some other players' runes and masteries on the "Runes" or "Masteries" tabs, and then suddenly I got invited to play a game, so I just went. We get to the champion selection screen and oh geez, my masteries are not my masteries! I cannot pick them, I see someone else's masteries with their names and set up. And if I try to pick one I get an error message on screen. I see the masteries of whoever I was watching the masteries on the lobby.

Steps to Replicate:

1. Go to the lobby of the client.
2. Enter a user account name to watch their stuff.
3. Click on the "Masteries" tab to see their masteries.
4. Get into a game without reseting anything that you were doing.
5. Try to pick one of the masteries possibilities.

Actual Result: Results for step 4. I see someone elses masteries, from the last person I was watching masteries on the lobby. Results for step 5. An error is displayed.

Expected Result: I see all my things correctly.

(I'm a QA myself so I know what I talk about lol)

IDK how to attach screenshots here, I have a couple. Contact me if needed.

Tech.