Reset "Connect as" under Yosemite / "connect to server"

I use AFP to connect to an (account on an) old MBP (Lion, off icloud) from my new MBP, latest Yosemite. I did not store the password in the keychain but it connects automatically. It says I am connected as my Apple Id (not as a registered user). If I click quick enough on "connect as", then the login windows pops up, prompting me to enter the user name and password. (The password field is blank.)

This does not happen from other accounts. I do not store the password and it does not connect automatically.

How can I reset this behavior? I do NOT want it to connect automatically.

Thanks in advance.