Local links converted to external links to OneDrive version of workbook containing the links.
Workbook links to data in worksheets within that same workbook have been redirected to the OneDrive version of itself. This was applied at Excel's initiative, not as a result of user's changes. Version is Microsoft Office 365 ProPlus Excel. "Use Office applications to sync Office files that I open" under File collaboration in OneDrive is unchecked.
I suggest removing this feature.