version: 15.1.8.3-c6240d38f (amd64)
If you use the pppoe for your wan as internet connection you will find the service name always auto fill num '1 ' after you save the config. Why?
It's a bug. Fixed in https://github.com/opnsense/core/commit/b2007f8c894a65e0d3c394e48b30480459d4996b
Thank you. Looking forward to releasing the new version.