Yes manually clearing corrupted definitions will fix this issue for you.
Revocation data' and 'Symantec Whitelist 12.1' are the components of Insight & receive updates frequently. So Revocation Data downloaded by default, not configurable from Symantec Endpoint Protection Manager.
If you are able to run liveupdate successfully, all these background updates should happen automatically. It may happen due to some definitions or DLL corruption.
Ensure that the "Reputation Settings" checkbox under "Content Types to Download" is checked. This will ensure that all the Reputation information used by the Insight engine is downloaded, processed and distributed to Symantec Endpoint Protection 12.1 clients in the organization
Centralized Reputation Settings 12.1" appears not to update in Symantec Endpoint Protection Manager