Export usage report to csv, have question marks in first column

I export usage report following this article.

https://blogs.technet.microsoft.com/dawiese/2017/04/15/get-office365-usage-reports-from-the-microsoft-graph-using-windows-powershell/#comment-22155

Script

https://gallery.technet.microsoft.com/Get-Office365-usage-f955ade4

When i exported report, It got 3 question marks in 'Report Refresh Date' column.

How can i remove question marks when exporting report?