The 're' is prepended at the time of sending. It is not a part of the actual subject, but an email signal to recipient.

The 're' is prepended at the time of sending. It is not a part of the actual subject, but an email signal to recipient.

If "Re: " is not part of the actual subject then why is it present in the Subject field of the message composition window when I am typing a reply?

Please read my response. It is prepended. Debating it doesn't change it. I am not defending it, only advising on what is happening.

I am not defending it, only advising on what is happening.

So if I start a new email from scratch, instead of replying, and I manually type "Re: " at the start of the subject, would you expect the copy in the IMAP folder to differ from the one the filter copies to Local Folders?

Hi triatica,

I understand that you are talking about “Re:” being removed from a subject header when you reply to a message that already has it.

This is a mystery to me. Would you please share a screen image of the filter rules?

Screenshots as requested.

Nothing stands out to me. My only idea is a general troubleshooting step. Start Thunderbird in troubleshooting mode and see if the problem persists.

≡button > Help > Troubleshooting mode

It seems to be a known bug.

Good find. I wondered and should have looked.

I did initially check but "Filter after sending not working any more" didn't seem to fit my issue, as it does work for me apart from the "Re: ". It was only when I opened my own bug report that someone said it was a duplicate. Anyway, the main thing is that it's being fixed!