JobEndNotification logs are not written by MRAppMaster and JobEndNotifier classes even though Log.info is present. The reason was MRAppMaster.this.stop() has been called before the JobEndNotification and hence somewhere during the stop log appenders also made null.
AM container syslog is not having below logs from JobEndNotifier
Job end notification trying + urlToNotify
Job end notification to + urlToNotify + succeeded / failed