Hello Ben,
Per the description shared, I understand the concern facing at your end but when I check the behavior, the columns with responses are in the General Format. So, I would like to request you to share a screenshot of the problem facing at your end and the duplicate form, so we can duplicate it to test at our end.
To share the duplicate form: Open the Form> Share> Share as template> Get a link to duplicate> Copy> Share it with us.
Best Regards,
Chitrahaas