Clear alert on No data

If this is specific to Cloud monitoring, they should be accounting for this. They don't alert on No Data but instead use Complex Datapoints with statements like "if(un(ReadsPerSecond),0..." so that if the value is No Data (aka unknown) it saves it as a 0. DataSource AWS_DynamoDB is an example of this. If you're not seeing that, you may need to upgrade your modules.

In a general case, when you have a real event-based item to check, where there is no real end time, EventSources may be better option to use. It will cause an alert when the issue is detected and automatically clear after x minutes.