I have created a module that performs a custom import following the documentation here. The import works, however, in order for the changes to show on the frontend the catalog_category_product index needs to be reindexed.
After inspecting the core Magento CustomerImportExport, I followed what was listed in the corresponding import.xml for declaring the index (see my file below)
<entity name="catalog_position" label="Catalog Position"
<!-- Indexes to be run after import -->
<relatedIndexer entity="catalog_position" name="catalog_category_product" />
Unfortunately, this index never seems to fire. It is set to "Update on Save" in the admin, and I confirmed running the php bin/magento indexer:reindex catalog_category_product reindexes successfully. It almost seems as if it's not picking up the relatedIndexer (though I have cleared caches, ran setup:upgrade, di:compile, the whole nine yards).
Any advice/suggestions would be greatly appreciated.