The system-generated e-mails about unread notifications in the global inbox are not being sent out to some users. It seems that this is happening for users who have never checked their inboxes on the site.
Since users can configure the e-mails to be sent out once every three hours/day/week, there must be some sort of check to figure out which messages are unread and how long they've been unread for. I suspect that this check is against the last time the inbox was opened, and a null value results in the system not understanding how old any messages are.
Steps to reproduce:
- Create new user.
- Upon logging in for the first time, there will immediately be a message in the inbox, appearing as a red
1in the top bar. DO NOT CLICK THE NUMBER, DO NOT READ THE INBOX!
- Go to your new user's profile, to the preferences page, and set the option to email you unread inbox messages every 3 hours:
- Post something that'll generate a response and won't get deleted quickly.
- Wait for a response. The number in the top bar will increment - DO NOT CLICK IT.
- Wait an additional 3 hours. Maybe make it 4, just to be sure.
- Note that you haven't received any emails about the response you got in step #5.