After selecting RPC as the protocol for Symantec Protection Engine (SPE), SPe does not manually trigger a LiveUpdate either through creating the LUNowFlag file or by clicking the Run LiveUpdate button in the local Java based UI.
Upgrade to SPE 9.0.0. to re-enable manual LiveUpdate.
If you are not able to upgrade immediately, to workaround, select ICAP as the protocol, restart the service, then manually initiate LiveUpdate again.
Remember to return to RPC mode and restart the service after this workaround.