This sometimes happen with my account as well, but weirdly now these Notification emails are getting caught by the Yahoo Mail's SPAM folder, lol. Sometimes I don't receive any notification though.
Anyway, on a serious note, I presume you have checked the following 2 options as well., See the screenshots posted below. I found these links in the footer part of the email which I have been receiving when I'm 'Watching" any thread/Topic.
I presume you have checked the "Unwatch" button/option as well, which unfortunately we need to do for each Topic individually, assuming other stop notification options
are not enabled/checked.
I think here we need to check the LAST option, "Stop all emails from Tom's Hardware Forum.