Two forms load thank you pages differently

We have two pages with IS forms embedded in iframes. During development, the thank you page for each form would load in the iframe. Now that we’ve launched the site, one form loads in the iframe and the other form loads outside the iframe (a full page). Both are configured exactly the same. I can’t figure out why the different behavior.

https://handsathomecareservices.com/contact/

https://handsathomecareservices.com/care-inquiry/