are you sure the excel is actually empty? if i’m not mistaking, the “read range” will read the equivalent of “used range” in vba. meaning that a cell format, font change etc. might trick the app into thinking that cell has a value
there are some strange behaviors in sharepoint - i had some troubles in the past with the sharepoint modifying the files and inserting some data (probably used for some internal content indexing?). not sure if there is a resolution for this.
eventually you can check what the datatable actually contains in that row…