It's weird because I applied using the version of June 2018 (CIT 0002 (06-2018) E) and in that version, they don't ask you about marital status
Do not worry about it as long as you used a version of the application dated Oct 2017 or later you should be fine.
Make sure you use a version of the application form dated October 2017 or later. You can find the version date on the bottom left corner of the form. For example, “CIT 0002 (01-2019)” means the version date is January 2019. The date you sign or mail your form does not change the version date.
If you submit your application on a form with a version date older than October 2017, we’ll return it to you and ask you to resubmit your application using the
newest version of the form.
If you used a version of the form dated October 2017 or later and we returned it to you as incomplete, you don’t need to use the newest version of the form to resubmit your application. You can resubmit it using the same form once you get the missing information or documents.