it doesn't appear that setting as-override in vyos 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