When I overwrite an Excel file on Sharepoint using the Sharepoint Online Connector + Excel Writer on KNIME 4.3.1, the existing online file would be deleted, and then a new file re-created. the side effect of this is the removal of OneDrive/Sharepoint sharing permissions that are configured directly on the old overwritten file. Sharing permissions that are configured through the folder won’t be affected.
The workaround is to use the Excel Writer (deprecated) from pre-KNIME 4.3.0. I’m also considering to write into a local Excel file that is being synced with OneDrive/Sharepoint using the Microsoft OneDrive desktop app.