Use attached to reproduce.
- Edit random cell and press Enter.
- Check the CellValueChanged event handler, the changes variable is null.

This will work if you comment the OnShown method.

Workaround:
IEditableObject editbaleObject = radGridView1.CurrentRow.DataBoundItem as IEditableObject;
if (editbaleObject != null)
{
     editbaleObject.EndEdit();
}