I have a pair of A12 devices (one is now A13, but that’s irrelevant for this). One of them is a legacy device and the other is newer.
The legacy device can be locally discovered by my PC. But not the newer one. For that I need to manually enter its LAN IP address.
The only relevant difference between the two I can think of is MAC randomisation. The legacy device doesn’t have the hardware, so the feature is unavailable there. The newer one has it.
Otherwise, just being on A12 doesn’t explain why my legacy A12 device and PC can discover each other.