Hi d_g_schaefer,
Thank you for your message in this forum.
According to your description, it seems that you cannot pin the specific file to list in Excel.
May I know if the scenario above is consistent with yours? If so, since this problem only occurs on a specific file, we’d suggest you go to OneDrive and create a new Excel file, then you can open it in Excel and pin it to list to check if the same problem will occur. If it works, we’d suggest you copy the content of problematic and paste it into new file to check if the same problem will occur.
If the problem still persists after trying the suggestion above, could you go to Excel > File > Account and provide the screenshot of Product Information?
Best Regards,
Sukie