Are you sure whatever hosts which reporting property results as “Not Reported” are actually subscribed to the site where these properties are hosted?
if Yes, 1st try to just restart the BESClient service & see if its getting processed or not.
2nd delete __BESData folder & check again in sometime.
If above both options are not working, you can enable below client setting to set the equal priority to each & every site not just the Master Operator Site. Sometime it could be possible the moment client trying to process your site, process was halted due to Master Operator site action which took the priority.
You can also look into these setting if you have set something like below for <2% CPU usages. below setting is restricting their CPU usages in normal mode (these client set for <2% CPU usages), where client awake for 10 miliseconds & went back to sleep for 480 miliseconds for normal processing like - processing actions, receiving force refresh, receiving udp messages, running .sh, processing a shutdown command, gathering sites and preparing reports.
& change them to default as below for those devices which will give client some extra time to process the things.
However these steps are mostly depended what you are seeing in BESClient Debug logs hence I would recommend 1st enable BESClient debug logging on 2-5 machines & re-subscribe those content to see what is happening against content ID when they are landing in debug logs.