Hi Rachman,
Greetings from syncfusion support
We can reproduce the reported issue at our end. We have considered this as an Improvement task and logged this as “columnName is not available in the actionBegin and actionComplete event args on ungrouping”. At Syncfusion, we are committed to fixing all validated defects (subject to technical feasibility and Product Development Life Cycle ) and will include this implementation in our upcoming patch release which is expected to be rolled out on November
11th , 2020.
You can now track the current status of your request, review the proposed resolution timeline, and contact us for any further inquiries through this link.
Regards,
Rajapandiyan S