If you have ever wanted to make a change on an existing field on a Marketo form, but didn’t see the changes reflected even after approving the form and landing pages, you are not alone. I contacted Marketo support with this issue and their fix isn’t a fix at all. You have to go into your form, delete the field and then add the field again. Once you do that, you should see the correct fields showing up.
The problem showed up for me when I was using a form with a Select field and using visability rules and predefined values. When I would just update the values, they wouldn’t show up on the landing pages but once I deleted the field, re added it and approved the form, every worked as expected.