I have a domain in virtualmin with a couple of alias domain (the target domain is example.cz and aliases are example.com, example.sk and some other). There is a mailbox email@example.com in the target domain and there is set up to copy aliases from target for all alias domains. I disabled (alias domain) example.com for few days. When I re-enable it, mail address firstname.lastname@example.org was not functional, until I switched the alias method to catchall and back again. Then the mail was functional again.
Is it possible to be a bug?