Applications not being discovered by client

I am using SCCM 2012 R2 and have 2 applications made available on a collection. Clients on the collection are taking about a week sometimes to discover the available apps under 'Software Center'. Eventually they are discovered. This happens with only some not all clients. No trace of the application in appdiscovery.log and forcing "machine policy retrieval and evaluation cycle" gives the below snippet on policyagent.log

Requesting Machine policy assignments
Requesting Machine policy from authority 'SMS:MPSRV'
Synchronous policy assignment request with correlation guid {B699AD99-6BC8-4FC4-BB86-37F51B93941C} for Machine <machine_name> completed with status 8000000A