Thank you! Removing Parent.Default on Attachments worked for my form that was showing old attachments. I also had other fields showing old data. The problem started for me when I published the form in Edit Mode with existing data. If you remove the Parent.Default from other fields they will not save back to SharePoint. To fix the caching issue, I had to change the default mode of the form to "New" and clear all the data out before publishing again.