We did not notice any issue in the output Excel file as you mentioned. Would you please make sure to use the latest version of the API and in case you still face any issue, please let us know.
But your attached file is the same as the picture at right-hand-side part of previous attached file “compare.png”. Notice the staircase pattern recognized compared with the online version (at the left-hand-side part of “compare.png”)
Yes, we were able to notice the similar issue in the generated Excel file using Aspose.PDF for .NET 20.12. We have logged an investigation ticket as PDFNET-49244 in our issue tracking system to further analyze the reasons behind this issue. We will further look into its details and keep you posted with the status of its correction. Please be patient and spare us some time.
Upon initial investigation, it is found that this is a regression that appeared in version 20.11 (the online version used some early version). Please try to use version 20.10 while this bug is not fixed. We will update you in this forum thread as soon as the issue is fixed.