https://github.com/cloudfoundry/uaa/blob/develop/uaa/src/main/webapp/WEB-INF/spring/oauth-clients.xml#L51-51

IIRC, If you switch to another profile, like mysql or postgres (the two default CF profiles), the default clients are not added. So it seems as you effectively removed the login client. The login client is CF specific, and should be defined in the manifest. The only reason it exists in 'default' is for integration testing and simplicity to startup.