Avahi daemon has a long-standing issue [1] where spurious name conflict keeps occurring for hosts on a network. There is a long discussion thread on the specific subject in that issue thread.

I have seen this more prevalent after switching to VyOS and a bit of digging into this led me to consider dual-stack network a key suspect. Hostname collision does greatly reduce if I have avahi-daemon running on either IPv4 or IPv6, but not both. Additionally, disabling publishing AAAA record over IPv4 and publishing A record over IPv6 as suggested [2][3] also helps. The conflict is still there if I have a host quickly switch LAN/VLAN of the participating interfaces but that's kind of expected.

Currently, VyOS config mode does test for valid participating interfaces and if they have IPv4 addresses, but it does not apply a similar treatment for IPv6 and blindly enables both IPv4 and IPv6.

While my observation is anecdotal, it still might be worthwhile to at least have an option to allow some user control on enabling the avahi-daemon IPv4/IPv6 network.

[1] https://github.com/lathiat/avahi/issues/117
[2] https://bugzilla.redhat.com/show_bug.cgi?id=669627#c2
[3] https://github.com/lathiat/avahi/issues/117#issuecomment-1651475104