it doesn't appear that setting as-override in vyos applies it to running frr config
here's the config i dropped into my test vyos vm
vyos@pe1# show protocols bgp | commands set address-family ipv4-unicast redistribute connected set local-as '64512' set neighbor 10.254.1.2 address-family ipv4-unicast set neighbor 10.254.1.2 remote-as 'internal' set neighbor 10.254.1.2 update-source 'lo' set neighbor 100.64.10.2 address-family ipv4-unicast as-override set neighbor 100.64.10.2 remote-as 'external' set parameters log-neighbor-changes
and here's what comes up in vtysh:
router bgp 64512 bgp log-neighbor-changes no bgp ebgp-requires-policy no bgp network import-check neighbor 10.254.1.2 remote-as internal neighbor 10.254.1.2 update-source lo neighbor 100.64.10.2 remote-as external ! address-family ipv4 unicast redistribute connected exit-address-family
if i manually enter as-override into frr, the config/topology i'm testing with works as expected