@cedivad oh yes, this makes sense for bluegreen. The propagation delay is masked with a rolling deploy because old VMs stay alive long enough for the new VM to get registered everywhere.
Blue green deploys stop all the existing VMs at once. This is happening faster than the new VMs get registered. You may be able to workaround this with a shutdown_delay and some code to catch SIGINT and delay shutdown of the app. It’s gross as heck and you shouldn’t need to do that, but it might work.