Initial content export not exporting all recommendable content

Question: Some of my articles are not exported in the initial export although they are marked as recommendable. Why does that happen?

Answer: Some fields are mandatory when you want to export an object to the eZ Recommendation service. In the publisher solution it is mandatory to have a valid from and a valid to (often mapped to publish date/unpublish date) different from 0. In the shop solution the price must be different from 0. Fill the price or the valid from/to fields and the content export should work also for this object.