Had the same problem, this worked for me:
You can rename the LocalHostName separately from the Computer Name, which should give you the desired result, and shouldn't mess with any network settings.
Under System Preferences -> Sharing, click the Edit button to the lower right of the Computer Name field. Here you can enter a different local hostname, and leave the computer name set to whatever you want the Bluetooth name to be.
If you explicitly need to set a hostname, you can also do that from Terminal, by entering:
scutil --set HostName yourhostnamehere
Before you do that though, you might want to check the current values. You can use these commands for hostname, local hostname, and computer name respectively:
scutil --get HostName
scutil --get LocalHostName
scutil --get ComputerName
An explanation of each of the properties can be found here:
ComputerName is the so-called “user-friendly” computer name for a Mac, it’s what will show up on the Mac itself and what will be visible to others when connecting to it over a local network. This is also what’s visible under the Sharing preference panel.
HostName is the name assigned to the computer as visible from the command line, and it’s also used by local and remote networks when connecting through SSH and Remote Login.
LocalHostName is the name identifier used by Bonjour and visible through file sharing services like AirDrop