This does fix the OStree issue, but EL7 and now also EL8 fail to sync the proxy with:
Katello::Resources::Candlepin::Owner: 404 Not Found {"displayMessage":"Organization with id Default_Organization could not be found.","requestUuid":"aa69f751-23cf-412b-914d-17378f312098"} (POST /candlepin/owners/Default_Organization/uebercert)