Errata still showing "Could not calculate errata status......." but I'm using remote execution not K agent

So status of the host is “warning”, due to errata showing “Could not calculate errata status, ensure host is registered and the katello-host-tools package is installed”
I have set admin->settings->content to “Use remote execution by default =true”

Is there any remote execute mechanism to replace the need for katello agent?

I can use remote execute to
“ping google!” (of course!)
add packages
remove packages
“yum clean all”
etc etc

I set all repos to “mirror on sync =no” and without doing anything else all the test clients turned green.
I think I may have been hitting capacity issues (df -kh showed 9GB of free capacity).
I was not notified on any repo issues, all repos syncs were succesful prior to re-configuring the “mirror on sync”