In Connect, there's an option to update the form and will it convert the XLS form to the latest version. You can also just add the column manually and as long as the column name is spelled correctly, the application will recognize it and honor the settings.
I cannot find the option in Connect to update the form, but I was able to copy and paste values of the column into the old form. If you could show me where the option to update is, that would help?
I highlighted it in red in my post. Under Tools. You probably need to go update your Connect here. https://www.esri.com/en-us/arcgis/products/arcgis-survey123/downloads
Is your Connect up to date? Older Connects don't have this option.
You can literally just add the column and it will work.
But also if you upgrade your Connect there is now a way to update in there.
I also posted the old school way to do it somewhere. Basically start a new form, copy paste values! column by column, save, then swap out the xlxs in the folder.
hope that helps