When I reply to emails that I copied myself on, it doesn’t put my own sender address on the outgoing email. It uses another of the accounts that are configured in my EM Client.
For example, EM Client is configured with 3 accounts:
Account 1 (default)
Account 2
Account 3
I send an email to several people and put myself on the CC (Account 1). If I respond to that message, it gets sent from Account 2 instead of Account 1, even though I’m currently in the inbox of Account 1 when I click reply. I have to remember to change it before I click send.