It is not a petty squabble! @RichardHaselgrove posted a question regarding how the forum functioned and it was answered.
As far as I am aware you will be unsubscribed from all the thread replies, however it may be the case that if somebody replying to your actual post by clicking on your post and using the reply button it will still notify you.
If you click on your Avatar at the top right and click on "My Subscriptions" it gives you various options to play about with and there may be one that will allow what you want.
If it is ticked by default I would suspect it is active.
I do not have your email address or any other information other than what you or any other member has shared in their public profile as seen by clicking on their avatar/user name.
You can PM ( private message) forum members by clicking on the envelope icon in the forum menu bar above.
Well, it's still broken. This received 5 minutes ago: