Hey, I think I might have encountered a bug with the variable references. The bug happens when a service tries to reference another service env variable but the other service has a name that requires quotes to be referenced.
For example, kitchen-sink-0.20.0-server tries to reference the client service URL like this https://"${{ kitchen-sink-0.20.0-client".RAILWAY_PUBLIC_DOMAIN }}. The value of the env variable turns out to be http:// when accessed by the server.
I've created a small reproduction here in project with ID: cd9b3605-236d-452d-b828-1900a94e6e8b (see screenshot for what I set and visit https://kitchen-sink-0200-server-production-e522.up.railway.app/ to see what the app received)