Configure the header entity in composite entity for with auto generated column,
Importing multiple files using recurring job at high rate of import will throw error on some messages to error out.
The error description will show duplicate number sequence for the specified column in mapping.
The fix delays the number sequence assignment within a transaction to avoid number sequence conflicts.
The workaround is to delay the import of composite xml files by a few seconds.
The issue is intermittent and may not always be possible to reproduce in lesser rate of messages.