What might be the reason (or is it by design) that if we open Excel Files from our on-premises SharePoint 2019 we get this waring ribbon saying "READ-ONLY We opened this workbook read-only from the server --> Edit Workbook", while this is not true for a Word or Powerpoint documemnt form the same location.
If I open an Excel from my OneDrive for Business it also does to show this warning.
Both locations are defined as Trusted Locations for all Office Apps via GPO. There is no Vesioning or checkout configured for that SharePoint library in charge, definitely no Require Checkout.
kind regards,
Dieter


