Thank you for sticking with this, @parkdanil!
I’ve now removed the Category from all of the posts in our site.
When I go to https://chrisandlisa1.wordpress.com/category/running/ and https://chrisandlisa1.wordpress.com/category/family-history/, the behavior is the same. Top of the page shows ‘Category: <categoryName>’ and under that there is a list of all of the posts in the site.
When I go to the specific pages that we published, https://chrisandlisa1.wordpress.com/running/ and https://chrisandlisa1.wordpress.com/family-history/, the page says ‘No results found’, which is expected at this point.