Reenabling alias server loses mail aliases (possible bug)

I have a domain in virtualmin with a couple of alias domain (the target domain is and aliases are, and some other). There is a mailbox in the target domain and there is set up to copy aliases from target for all alias domains. I disabled (alias domain) for few days. When I re-enable it, mail address 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?