Why don’t I get ‘discussions’ emails any more?

I still get the tech news I’ve subscribed to, but not notices about the off-topic Discussions. And I make sure the box is checked before I hit submit, on topics I want to follow. But I haven’t gotten any of those emails about new posts to my discussions since about the time of the most recent updates to the page designs. I’m going to check the box on this one, too: “Notify me by e-mail when new posts are added to this thread.”