Shared spreedsheet not merging changes.

My co worker has a spreadsheet she updates everyday. It is on a folder on her OneDrive which is shared with me. If I open the file in the webapp I see the latest file but if i open it on the desktop app I see the file as at 27-Sept-2022. On the desktop app I am unable to make changes and merge with her file. I am using Excel 2019 and Office 365.

Can't understand what's going on because it was working perfectly a couple weeks ago.

I figured it out. You need to delete the cache.

To me, it seems that Onedrive/Sharepoint has caching issues and can corrupt your files, especially files being used as data sources or being modified by multiple users. Check the option to delete the cache on closing the workbook just to be safe.