Yes, Scrambler, I get only posts of the same category. Yes sorting by date is the default for WordPress.
Weaver, I am not doing anything special, I am using a plugin called flex blocks, that (in block mode) allows me to specify a query to pull posts of a specific category, and display them in a specific way. Once the user clicks on a post (item), then it goes to a single post page, with next and previous options.
I can confirm that if I select the category bee, from themes, that 11 items show up correctly and there are no missing items.
All the bee items have now only one category. So what would cause items with multiple categories to not show?