If you are using 'Run client task now' option, then for enable task to succeed, an ASCI must happen b/w the end points and ePO.
Do a wake up agent on end points after you deploy the product, check system properties on ePO showing Solidcore status as Disabled.
Then invoke enable client task from 'Run task now' option.
Thank you, I'm testing the solution as I type here
It works. The devices are solidifying!
Many thanks for your assistance.