Change 214049 had a related patch set uploaded (by Matthias Mullie):
Only import unread LQT notifications

https://gerrit.wikimedia.org/r/214049

I can keep looking at this, but couldn't find anything so far:

• All notifications that could be fired when storing data should be ignored by the $metadata['imported'] check in NotificationListener.php
• user-locators & EchoGetDefaultNotifiedUsers hook are properly killed in LqtNotifications.php
• They are killed before any notification could even be triggered
• We trigger 1 notification from LqtNotifications::afterTopicImported, that should only be sent to LqtNotifications::locateUsersWithPendingLqtNotifications

It all seems to work perfectly fine, and I am unable to reproduce the problem. Maybe this has already been solved, but I could not reproduce this problem with code from back when this was filed either.
I can keep looking, but maybe someone else could try if they can reproduce it, before I waste more time on something I can't properly debug?

Oh, the patch I have up makes some minor changes, but it shouldn't make a difference. In essence, I can't currently find anything wrong with the existing code.

Change 214049 merged by jenkins-bot:
Make sure no other user-locators cause notifications during lqt-import

https://gerrit.wikimedia.org/r/214049

Change 215271 had a related patch set uploaded (by Mattflaschen):
Fix users getting notifications despite not having Special:NewMessages.

https://gerrit.wikimedia.org/r/215271

Change 215271 merged by jenkins-bot:
Fix users getting notifications despite not having Special:NewMessages.

https://gerrit.wikimedia.org/r/215271

Change 215405 had a related patch set uploaded (by Mattflaschen):
Fix users getting notifications despite not having Special:NewMessages.

https://gerrit.wikimedia.org/r/215405

Change 215405 merged by jenkins-bot:
Fix users getting notifications despite not having Special:NewMessages.

https://gerrit.wikimedia.org/r/215405

This happened again on mediawiki.org?
PS: On second thought, I don't know if those pages were unread or not. I just didn't appreciate being flooded with emails and having a red "40" notice on wiki.

yep this also happened to me yesterday. I got 150+ e-mails and it's likely other people got spammed in a similar way. I'd ask that this is considered a higher priority to fix as it gives a bad first impression of Flow.

Please post screenshots of your emails. MediaWiki has lots of different email notification types, and I need to know for sure what kind you got.

If it's more than one type, please post a screenshot of each type.

I got 62 of these :

Thanks, @Jdlrobson. That is indeed T101540: D42. Flow talkpage conversion (LQT->Flow) should not send an email to users with enotifwatchlistpages about the page move or redirect creation.