Vault login problems

Elder Scrolls Online has two seperate accounts - one for the game and one for the forums.

N360's vault treats both of these as the same one.

When I try to login to my game account it will auto fill in for forum account as that's the last one I saved.

In order to login to the game account I have to close the vault and do it manually.

Why does N360 treat these two logins as the same one?