Return-Path modified

[Eugene Crosser <crosser@online.ru>]

Apparently recent router modifies Return-Path in an indesired way.
I have primary domain "online.ru" and a lot of virtual domains that
are all in "localnames" database.  If a user form such virtual domain
sends mail, e.g. <user@virtual.ru>, the message is passed to the
transport agent with envelope from <user@online.ru>.  In the logs,
still "user@virtual.ru" is seen but in reality it is "user@online.ru"

It seems that this (mis)feature has appeared only in the most recent
versions.

Any ideas about this?

Eugene