I have a legacy email address + 3 other chat relays in one profile.
Delta chat downloads e-mails from legacy e-mail address and doesn’t keep the copy of downloaded e-mails on the server!
My Settings: Chats/Delete Messages from Server: Never
Android, 2.43.0
That should not happen. I hope you didn’t lose anything important.
Are you sure the deleted mails were ever on the legacy server? Could they have been on one of the other servers linked to the profile instead? Messages are sent to the last-seen address, so unless the last message you sent to Alice was sent from the legacy address, she won’t reply to that address.
If you are sure the messages were there and were deleted by the DC client, a logfile from the client would be handy.