Local mails on mx server to provider domain is delivered to vmail maildir even if the user doesn't exist

echo test | mail noone@try.pixelated-project.org

from mail.log:

Dec 10 14:50:41 pixelated postfix/pickup[2124]: 431E483675: uid=0 from=
Dec 10 14:50:41 pixelated postfix/cleanup[15225]: 431E483675: message-id=<20141210135041.431E483675@pixelated.try.pixelated-project.org>
Dec 10 14:50:41 pixelated postfix/qmgr[10753]: 431E483675: from=, size=352, nrcpt=1 (queue active)
Dec 10 14:50:41 pixelated postfix/local[15230]: 431E483675: to=, orig_to=, relay=local, delay=0.16, delays=0.09/0.01/0/0.06, dsn=2.0.0, status=sent (delivered to maildir)
Dec 10 14:50:41 pixelated postfix/qmgr[10753]: 431E483675: removed

(from redmine: created on 2014-12-10, closed on 2015-01-06)