Comment counter; No comments found.

Hi,

Recently I noticed that the comment counter in the backend indicates that there are 16 pending comments, but when I open the comments-tab I don’t see any comments: “No comments found.”

I disabled all plugins and switched the theme to twentynineteen. This changed nothing except that now the comment counter of ‘approved’ comments also shows a number (689), this was not visible earlier.

What could be the problem?

Thanks!