I am encountering a peculiar issue with the "Reply to All" functionality in Thunderbird, which I believe may be a bug or an unintended behavior within the application. I hope you can provide guidance or a solution. Issue Description: When I attempt to "Reply to All" to an email that I previously sent (which is the last email in a conversation thread), Thunderbird automatically alters the sender's address. Specifically, instead of maintaining me as the sender, it changes the sender to the one (or the first one, if there's more) of the original recipients' addresses. As a result, the email appears as if it's being sent by the recipient back to themselves. This messes with the recipient's folders and rules, as the message has no indication it's been sent by me. This happens when I initiate the "Reply to All" action from the Sent folder on emails where I was the original sender. This only happens in one of the email accounts I'm using in Thunderbird, and it's a POP Mail Server type account. Steps to Replicate: Send an email to one or more recipients. Go to the Sent folder and open the email that was just sent. Click on "Reply to All." Notice that the sender's address is automatically changed to one of the recipients' (typically the first one, if there are more recipients). Expected Behavior: The sender's address should remain as my email address, not change to a recipient's address, ensuring the email is correctly identified as being sent by me to the other recipients. Troubleshooting Steps Already Taken: Verified that no extensions or add-ons are causing this behavior. Checked for any relevant settings within Thunderbird that could influence this behavior but found none. Updated Thunderbird to the latest version available. I would appreciate any advice, solutions, or workarounds you can offer to prevent Thunderbird from automatically changing the sender's address in this scenario. Please let me know if there are any logs or additional information I can provide to assist in resolving this issue.