Inverse relationship plugin doesn't seem to work

I have a very similar use case to the default use case for the inverse relationship plugin. I want to display a collection of tours (posts) for each agency (author). However, after following the steps to setup the plugin, this does not work for me.

I have attached a screenshot of the settings for the plugin on the JSON field on agency.

hi @ben3

slug fields cannot be used for sorting, Try to use name_DESC instead!