I deleted virtual server koe.com. Deleting that also deleted mail aliases from other virtual server. Other virtual server had 5 aliases and deleting operation deleted 4 of them. I confirmed this by taking a diff of my daily logs of postfix virtual file.
Also webmin actions log tells
Changed file /etc/httpd/conf/vhosts.conf
272,273d271
< ServerAlias moikka.koe.com
< ServerAlias www.moikka.koe.com
A lot below
Changed file /etc/postfix/virtual
313,320d312
< koe@koe.com koe
< koe.com koe.com
< abuse@koe.com koe@koe.com
< webmaster@koe.com koe@koe.com
< hostmaster@koe.com koe@koe.com
< postmaster@koe.com koe@koe.com
< @koe.com BOUNCE
< domain@domain.com domain
322,325d313
< zzz@domain.com www
< yyy@domain.com eee
< xxx@domain.com rrr
< kkk@domain.com ttt
Mail addresses changed. How can something like this happen???