Thank you for your answer,
I exported a excel from the online demo, with the same problem.
I have analyzed this problem and found that there are several custom formats of excel that are not recognized. Please look at picture 1 .
This problem occurred after a Microsoft update on August 13, and it would not have happened until then. The update package was KB4032241 (Office 2013).
If you have any solution, please let me know as soon as possible.