Why Power Query sees one excel file as error?

Hi there, 

I try to connect to sharepoint specific folder, grab all of the files, merge then and do some other stuff with it. I use code as below: 

let 
Source = SharePoint.Files("https://my-company.sharepoint.com/sites/My-folder", [ApiVersion = 15]), 
#"Filtered rows1" = Table.SelectRows(Source, each Text.Contains([Folder Path], "First")), 
#"Added Custom" = Table.AddColumn(#"Filtered rows", "Custom", each Excel.Workbook([Content])) 
in 
#"Added Custom"

In some strange reasons power query sees last file as Error.

Structure of all files are exactly the same, in the last file there is only less rows. 

Does anyone have an idea how to overcome my problem?