Documents not exposed when created in new content type based on basedocument

Based on input from Arje:

When I add a document of type myhippoproject:recipe then it shows up perfectly in the REST output.
When I create a new document type based on basedocument and then create and publish content of that type then this is not showing up in REST results.

Expectations:
Newly created content for any content type (new or existing) should be exposed in the REST output.

This test was carried out on the S2M implementation on onDemand v2, so it is worth us considering the potential cause being rooted in the OD2 platform if not present in the feature code.