openpyxl的bug

path = r'c:\......'

wb = load_workbook(path,keep_vba=True)
ws = wb['Sheet1']


((load_workbook(path,keep_vba=True))['Sheet1']).cell(1,3).value = 'abc'   ---(A)
ws.cell(1,3).value = 'abc' ---(B)

wb.save(path)

结果是B能正常保存，A不能。原因未知。mark