Docs insertion doesn't work with after_sync

Hi, I modified the “Identification Document Type” Doctype to add a new field, then exported the customization to my custom app. Now I want to insert some records to that Doctype on app installation. I tried using the “after_install” hook, but it runs before customizations are updated, so the docs are created without the new field. I tried do the insertions on “after_sync” hook, which runs after customizations are updated, but there the docs are not being inserted. It runs perfectly with no error, but when I check the list there are no new docs.

any idea what’s happening? Thanks in advance!