To start server:

./gradlew -p config-server bootRun&

You can tets it with:

curl localhost:8888/config-client/default

To start client:

./gradlew -p config-client bootRun

The expected result is "demo property value: Bob" being printed to stdout. The observer result is an exception being thrown.

The client uses Spring Boot 2.4.2. Downgrading it to 2.4.1 fixes the problem.