bobmoss said

I've recently moved over to Thunderbird and got my Junk filter well trained

kudos (assuming you've also trained many messages as Not Junk, and continue to do so). not every user gets that.

bobmoss said

but I've noticed that sometimes when new e-mail comes in the Junk mail controls are not run at all against the new messages. This isn't a problem with mail being marked as junk and not being moved, nor is it mail not being detected as junk. I have installed the Junquilla addon and added the "Junk %" column so I can see what percentage each e-mail. When the issue happens I can see that ALL the e-mail that has come in on that POP3 session is missing a percentage. It's not a zero percentage, it's a completely missing percentage - I.e. the e-mail hasn't been checked against the junk mail controls. If I select the folder and go and do "Run Junk mail controls on folder", it finds them all and classifies them correctly. It seems to happen completely randomly and once I notice it and do "Run junk mail controls on folder" it will start working again. I checked and compacted all folders and I've checked all the junk mail settings. Anyone else having this? Any ideas how to fix it?

Interesting issue. And good description. I'm not finding anything similar amongst reported bugs.

Nothing common to these messages - all English lanaguage, not-mime-encoded message bodies? Is the inbox ever accessed from somewhere/some-device other than Thunderbird on this PC?

xref https://bugzilla.mozilla.org/show_bug.cgi?id=1271189

Thanks Wayne - Yes, I've trained it on hundreds of good and bad messages and so it works quite well.

I've done some further testing on this and can reliably reproduce it and have figured out the exact circumstances that cause it.

So, simply put, if you are currently in a folder and a new message comes in for that folder by using the "Check for new messages every X minutes" option then junk mail controls are not run against that message and it is not scored for spam.

If you do a manual Send & receive it works OK.

I have tested this multiple times - I can go to any folder (I have several setup for various filters but it also happens with the "Inbox" folder) and from a web e-mail client send myself an e-mail which should filtered to the folder I'm in. As soon as the Thunderbird does it's scheduled check for messages the message drops into the folder I'm in without getting scored. Any other messages that come in at the same time that are not for the folder I'm in will get scored correctly.

I can reproduce this on any folder and any account I have setup.

I'm running version 45.4.0 under Windows 10.

Can anyone else reproduce this?

Should I raise this as an issue on the official bug tracker?

Thanks.

> Should I raise this as an issue on the official bug tracker?

Great work. Glad you asked. Yes - at https://bugzilla.mozilla.org/enter_bug.cgi?product=Thunderbird&component=Filters

xref https://bugzilla.mozilla.org/show_bug.cgi?id=1319429