Magento 2.1.3 updated the ranging in category product indexing, and inadvertently limited indexed products in a category to 500. :-( However, patching a single function can undo this limit until an official bugfix is released... which is what this does.
I think it's still in issue in newer magento versions - and newer mangeto versions can run a higher php version...
Can the max php version in composer.json be updated to <=7.2 ?