Import is marked "Success but no change to data

I am trying to update the following Item fields using a csv file on the ERPNEXT Cloud version:
Supplier Details - Item code for supplier:
Supplier Part Number:
The fields in Purchase Details:
The import is marked “success” but there are no changes in the item fields. Update Records is checked, Don’t create new records is checked and Skip rows with errors is checked. I have reloaded and modified the file various times and still no change. Sometimes when I upload the file it skips going to where you click on “import” and continues to the point that it says success.
I have downloaded the template with some manually filled in data to make sure I am filling in the correct headings but I still cannot see what I am doing wrong.
This is what a part of my upload file looks like.

Thank you for any help.