Batch Context Generator with start trigger and batch identifier tag may result in incorrect batch start or end times

Symptoms

When using the Batch Context Generator node with both a start trigger and a batch identifier tag the batch start or end times returned are sometimes incorrect. 

Cause

When data is populated in the node by doing Find batches, or when a project execution is using it, batches found can start and end too late compared to what you expect depending on the search window.

This problem occurs when a start trigger is used in combination with a batch identifier tag in a node.

This problem only affects Generator-type nodes, not Aggregation-type nodes. 

More information

When the Batch Context Generator reads process data to generate batches it typically starts with a data block corresponding to one maximum batch length back in time. The code checks if the start trigger is true to start the batch. It fails to check that the start of the batch was found, which means the start of the batch may be missed. 

Furthermore, occasionally a batch may be ignored with the debug-level log message 'Batch not saved due to start/stop being outside scan range' in the server log. 

Status

This is fixed in SIMCA-online 17.0.1.

A Generator-type node now requires that the batch identifier has changed in a data block before a batch is started, and always creates a batch at the first time when the start trigger is true.