I'm not exactly sure whether this is a bug or not. It has been this way for ages.

If you look at the "Last Connected:" row in serveradmin (ServerQuery), you always see the Date info: "12/31/69 7:00 PM". Interestingly, every time a serveradmin connects, "First Connected:" changes to the date of "last connected", while "last connected" row never changes.

It seems to me that devs have switched the update implementations on "first connected" and "last connected" for server queries, as they seems to be inconsistent with other users.

Senario 1: a normal user connects through virtual server's UDP port.
Teamspeak Server: If the user is not in the database, let first connected = current time.
Let last connected = current time.

Senario 2 (current): a user connects through server query.
Teamspeak Server: Let first connected = current time.

Senario 2 (suggested fix): a user connects through server query.
Teamspeak Server: Let last connected = current time.