I can’t figure out the exact workflow but it’s happened 3 or 4 times now so I know it’s systemic…
Saving a tag in preferences for notifications does not save. Sometimes this happens after I log-in / log-out and sometimes the saved tag disappears from the list.
Sorry I can’t manually reproduce, but, again, enough times and it’s caught my attention.
Without reproduction steps, there’s not much we can do…
Feel free to try as long as you want on https://try.discourse.org.
yeah. I’m going to just keep this bookmarked and i’ll come back to it if i can manage to repro it for you all. 
I just ran into this bug on my instance. Appears to happen when saving users preferences.
Repro Steps:
Observe: the notification setting for the tags are now gone.
Note: It appears to take time to lose the settings after the save. I did these steps, saw that everything saved and the returned about 1-2min later to find the tag notifications were removed. Seems correlated to saving other account preferences though.
@SquareTheBase Saving of each preference page is separate, so you should save the tag notification preferences and then navigate away.
Ah - forgot to note that step in my repro steps, but I did in fact save the added tags prior to navigating away.
I was able to reproduce. Hmm… Will look into it.
This applies to anyone, not only an admin changing someone else’s prefs.
I made a fix for this today. It’s probably been there for a while. People don’t use tag notification preferences very often? 
Thanks! I should have noted this earlier, but I think I saw the same issue within the settings view. Would your fix have been effective in that area?
The settings in admin? Or something else?
Yes, admin settings.
I removed the auto-generated email header, saved the setting… then navigated to the email notification time and saved that change. When browsing a bit later, the auto-generated email heading had returned.
This fix won’t impact the admin site settings so report that bug in a new topic please.