Can you get the Document and Sheet field directly? or did you fill the blank yourself?As after I select the right Document and Sheet fields , I got a Mapping Column Mode. But I don’t see one in your workflow.
I tested this and ran into the same issue. The solution was to change the format of the column name in Google Sheets to “string”. You can do that by entering the following in the formula bar:
="1"
instead of simply entering 1 in the cell. The former creates a string, the latter creates a number.