I've seen this happen before - a little trick that can be useful is to open the link in a private browser, then you can either see the comment if you've been blocked, or some sort of 'login to view this comment' if someone is blocking you + disallowing public views of their comments.
I assumed when it happened to me that someone had commented and then immediately erased the comment.
it's weird to see the comment count not line up with any sort of reality, but it's the new normal for sw, I suppose.