I'm not sure where the problem is, but the 'mail' command is trying to read the mail for the wrong user when issued from a new account.

Here's the mail output:
Note that its almost every user that does this (root at least, but that may have something to do with my /etc/aliases)

Also, it would seem that I can't check it via pop3 (dovecot + postfix), as my telnet session closes after I send the PASS command and get "+OK Logged in."

Is this simply a case of misconfiguration? Or is there an extra step needed to add mail users?

-Thanks

Oops, looks like my MAIL variable was carried over from su.
Adding an entry to the ~/.bashrc and running source on it seemed to clear up the issue.