When the DNS configuration (/etc/resolv.conf) is updated as described in the tech doc below, changes are lost when the Vapp is rebooted.
https://techdocs.broadcom.com/us/en/symantec-security-software/identity-security/identity-suite/14-5/virtual-appliance/administering-virtual-appliance.html#concept.dita_484b93c7f06198e8b27adcc2537229358eb17777_ChangingDNSConfiguration
Section: Changing DNS Configuration
Virtual Appliance 14.5 SP1
Engineering provided a hotfix to solve the problem. (File name: HF_VA-14.5.x-20240912112050-DE615589.tgz.gpg)
Please contact Broadcom support to receive this fix.