Old contributor forum thread won't stop generating notifications

I stopped using my SA account several years ago in part because I constantly get notifications every time anyone comments in a Contributor Forum thread I commented in once 4 years ago, despite the fact that I deleted my comment and turned off all notification settings I could find in an effort to make it stop. I'd like to start using SA again since I like many of the recent improvements colleagues have pointed out to me, but the constant notifications are too distracting. The name of the thread is "Let me know when you reach a round number." Please help!