Hello,
Thank you for your inquiry.
The free version of Spire.Office does have the issue you mentioned, but the commercial version fixes this error. Since we only maintain the free version irregularly. I suggest that you use our commercial version (the latest version is
Spire.Office Platinum(Hotfix) Version:6.12.0), which conatins more fixes and new features than the free one. We are willing to provide you with a one-month temporary license to evaluate without any watermarks and restrictions, please apply for a temporary license from this link:
https://www.e-iceblue.com/TemLicense.html. If there is any question, please feel free to write back.
Sincerely,
Annika
E-iceblue support team