I was having the exact same problem while querying post and pages, but also the jetpack-portfolio post type in my custom widgets.
I was using $query = new WP_Query( $query_args ); in both cases. For me the fix was to change $query to $query_entries and $query_projects. It works as expected now.
I see you’re already using $products, but maybe it conflicts with some other query you run. Try to change that and see if it does the trick.
UPDATE: Disregard that, it didn’t fix it. If I close the Customizer and come back to it, the widgets are still acting weird.