Encountered this error after updating a Survey123 Connect form. The error occurred on the web form, however I did not confirm if this error occurred on the app. The form uses a pull data function targeting a csv within the Files/media folder. The csv was updated and during editing I believe data may have been copied to adjacent cells causing S123 connect to interpret the column as possibly having data, even though there was no column heading nor visible data. The error was resolved after deleting several "blank" columns to the right of the valid columns and republishing the form.
Not sure if this is the best way to post a resolved issue, but figured it might save someone time.
Solved! Go to Solution.