If you still have those old Windows 2003 and 2008 pre R2 servers around, and you have a SCOM Agent on those, it could be – they are all in a grey state. One reason could be the Advisor/OpsInsights Connector – Currently the Advisor Intelligence MPs are running PS scripts against Windows without PS.

Fix: Override the Healthservice with a disable for those servers in a grey state (2003/2008)

More info:

https://social.technet.microsoft.com/Forums/en-US/cee7736b-f119-4d6a-ad81-18b3d9f7f4a9/grey-agents-after-new-management-pack-with-idmicrosoftintelligencepackstypes?forum=operationsmanagergeneral

See you