You request to know if SSL inspection should be bypassed for LiveUpdate in Symantec Protection Engine (SPE).
SPE 9.x
If your proxy is configured to perform SSL inspection, you must bypass SSL inspection for the external ports listed in document linked below. Otherwise some services, such as Insight and LiveUpdate, will not function due to pinned certificates.
https://techdocs.broadcom.com/us/en/symantec-security-software/endpoint-security-and-management/symantec-protection-engine/9-2-0/Configuring-and-Monitoring/networking-port-requirements-v128663338-d4995e37654.html