Hi Ian,
Thanks for the details!
I have found two issues actually. One was the incorrectly set post statuses, it was set to “published” while the correct term is “publish”: https://i.imgur.com/GIYNivQ.png
The second one is the custom field filters. It appears that those fields does not exist yet – or they don’t have assigned values yet. When I remove both, it starts working. I checked a few posts, but I don’t see any of those values set yet.