It’s an odd quirk with our stats system. The system is pretty simple—recording your site ID and your post ID. Since it is just that simple, it doesn’t record post types along with it.
When you have it set to 8 posts, it pulls the 8 top posts from the system, then checks for the ones that are posts (vs pages) and outputs that. In your case, one of the top few posts is a page while the rest are posts.
We’re investigating two routes to make this make more sense.
1. A total rewrite of how we access the stats from WP.com that would take post type into account ( https://github.com/Automattic/jetpack/issues/2196 ).
2. A “dirty” method of pulling down more than you ask for in the hope that you’d have at least the number of items you want of that particular post type (e.g. grab the top 50 and filter the top 10 posts from there, etc): https://github.com/Automattic/jetpack/issues/2369
You can follow along with both of those tickets to see the progress on that.
Cheers!
