I think I figured this out. I tend to read some stories that are recommended to me through email. I just klick on them. But when I want to comment, it says “you need to use your medium app to comment". So I go into my app, find the article through my reading list and make my comment.

There seems to be an issue where you get views but not reads when you don’t go into the article through the app. So people will clap for articles they did read, bit not through their medium app…