All emails sent from the ticketing module use the same address as the Email Reader's incoming address, even if they are different
This is by design.
The ticketing module is able to read emails from the specified inbox and either convert them in to tickets, or to add the message to existing ticket.
You, as a support person, update a ticket with a note.
This sends an email to the customer.
The customer replies
The email reader gets the reply
The email reader adds the reply to the ticket
and round we go.
What would happen if the email reader was looking at the inbox called firstname.lastname@example.org, but was sending emails with a "from" address of email@example.com?
The tech support person would add a note
The system would send an email from firstname.lastname@example.org to email@example.com
The customer would reply to that email - sending their reply from firstname.lastname@example.org to email@example.com
BUT, the email reader isn't looking at info@, it is looking at the support@ inbox. The reader would never see the reply - the customer would have received an email from info@, and so would naturally reply to info@, but the ticketing system is looking at support@.
For this reason, the ticketing module will always send the mail from the address that it is configured to read from - that is the only way that the system can be sure that mails that it sends get back to it when the customer replies.
RESOLUTION / WORKAROUND
This is by design, and as such there is no "fix" for this.