No longer getting email upon notification of activity in “Watching” category

I had set the “Release Notes” category to “Watching” and, for more than a year, it worked: I would get an email when steeven added a post about a new release.

But after not getting any for more than a month, I logged-in to the forum and saw that I had two such unread notifications from the previous three weeks. So that part still works.

Only the emails are missing.

And, yes, the required setting (i.e. “Email me when I am quoted, replied to, my @username is mentioned, or when there is new activity in my watched categories, tags or topics”) is still set to Always.

Has someone disabled something at a higher level?