'This computer’s local hostname “Macintosh-HD-562.local” is already in use on this network'

At random times, a message 'This computer’s local hostname “Macintosh-HD-562.local” is already in use on this network. The name has been changed to “Macintosh-HD-716.local”' pops up, with different HD.local numbers each time.

This happens all the time, never as the result of any action I can recall having taken to provoke it. I am using a Mac Pro 2019 16-core 96GB running Sonoma, and accessing internet via WiFi from a Huawei CPE Pro 3 5G router via the 5GHz port from a GP-Link WiFi Extender.