In current versions of VyOS relay-agents-packets in DHCP relay is dysfunctional due to misconfiguration.
If option is set, configuration script only add -m [value]to dhcrelay command:
if conf.exists('relay-agents-packets'): pkt = '-m ' + conf.return_value('relay-agents-packets') relay['options'].append(pkt)
But, this is not enough. According to Debian manual page, we also need to add -a key.
This is confirming also by dhcrelay source. Default value of add_agent_options is zero and can be changed only by -a key. And if add_agent_options is not 1, then whole add_relay_agent_options function, where performing processing of relayed packets with Relay Agent Information option, is skipped.
So, we need to add also -a option to command if relay-agents-packets is configured.