I started seeing a new issue on June 10th, 2025 that my Azure App Service staging slot was created with the name “staging”, but it became “stagingd5a1” in the domain name.
So four seemingly random characters were added to my slot name. This became a problem as my pipeline is running health checks on the deployment. These checks, however, are not run on the assigned name but on the expected name which suddenly was no longer correct. It would be possible to obtain the name and use it, but there are also other issues that can emerge from it. The website might not know what portal to return on a random hostname, CORS errors could occur on an unexpected domain.
Microsoft is generally pushing for more secure, randomly generated hostnames.
However, this is not the feature I ran into in this case.