When upgrading from earlier versions of Ambari, the alert definitions do not include some of the new parameters / connection timeout values which were added to the alert definitions. This is normally OK since the alert framework has sensible defaults of the values are not specified.
However, it was observed on Ambari 2.2.2 that the web client wasn't able to properly render/save the values.
Install Ambari 2.2.0
Upgrade to Ambari 2.2.2
You should now have alert definitions, such as DataNode Web UI, which do not have a connection_timeout value.
Navigate to the DataNode Web UI alert definition page and notice that you are not able to update and save the "Connection Timeout" property correctly.