Commented Unassigned: Problem opening workbook containing Table with no headers [9400]

Hi, I am receiving Object Reference exception when trying to instantiate an existing workbook having a table with removed Header Row. Using latest production ClosedXML.
Comments: Attachment added. Very simple. Just convert a range to a table without checking "My Table has headers". Excel will create header for it "Column1", "Column2" etc... Then go to table design and uncheck "Header Row"