macOS frequently adding a number to the name of my computer

macOS is frequently adding a number to -- or thereafter changing the number on -- the name of my MBP. Why is it doing that?

The popup help on the Sharing dialog box says "If your Mac has the exact name of another Mac on your local network, a number is added to the local network name." In my case, there are no other macOS devices on my network.

My MBP does have two connections: WiFi and wired. I notice that if I disable either connection macOS doesn't add/change a number. Is this scenario causing the issue? If so, is this a known/reported bug?

The wired connection provides the best throughput to the Internet ... and the WiFi connection is needed so that I can unlock the console with my Apple Watch as well as for network connectivity when I disconnect from the wire.

("Change your computer’s name or local hostname on Mac" (https://support.apple.com/guide/mac-help/change-computers-local-hostname-mac-mchlp2322/mac) explains how to change the computer name, myself -- but it doesn't explain why macOS keeps doing it on its own.)