@Mathieu: Have you tried on a server installed with ubuntu-18.04-server-amd64.iso??? And with netplan.io:0.40.1~18.04.2 package installed?? Because renames were not working properly before 0.40.1~18.04.2 and after that, renames were ok (both on boot and on netplan apply) but no other configs are applied on boot, just on netplan apply....
@Mathieu: Have you tried on a server installed with ubuntu- 18.04-server- amd64.iso? ?? And with netplan. io:0.40. 1~18.04. 2 package installed?? Because renames were not working properly before 0.40.1~18.04.2 and after that, renames were ok (both on boot and on netplan apply) but no other configs are applied on boot, just on netplan apply....