Team Builder Masteries Glitch

When selecting masteries in team Builder, you click the drop down list and choose from your list of masteries, correct? Well, that's not the case all the time. I found that if you view the masteries of someone on your friends list (Right click>View Profile>Masteries), you can actually transfer their masteries and make them replace yours

Steps:

1. View a friend's masteries
2. Click the home icon to go back to the Team builder lobby
3. Click on the drop down list. All of your masteries will be gone and replaced with the friend's for the duration of the lobby. To fix it, just view your masteries and repeat steps 2-3

Just wanted to point this out to Riot, because lower levels can use high level masteries. I didn't test it with rune pages, but it might be the same case.