It looks like you have two mail servers designed to act as the primary email recipient in your domain: Google Apps and your postfix server. You cannot do this because, as you have discovered, mail is sometimes delivered to one server, and sometimes to another.
, , Google Apps . , Google, . , .
/etc/postfix/main.cf mydestination. .
postfix, , , :
mydestination = $myhostname localhost.$mydomain localhost
, "test1", - "example.com". :
info@test1
info@localhost.example.com
info@localhost
info@example.com Google Apps, "example.com".