Apparently docker-compose ps only contains the image name from version 2.14 and older versions are still common in package managers (e.g. I had 2.12). The docker inspect result, however, always contains the image name, so you can fix it like this (in the constructor of DefaultRunningService):
this.image = ImageReference.of(psResponse.image() != null ? psResponse.image() : inspectResponse.config().image());