Passing URL paramaters to thank you page

Hey, I just started using the new landing page builder and have run into an issue where I don’t seem to be able to pass form field parameter values to the page following the form submission. This is something that I was easily able to do using the previous landing page builder. It just seemed to do it automatically as long as I had the field URL parameters populated in the back end.
For example, after I hit the form submit button on my old landing pages, any form URL parameters e.g. ?first=Bob&last=Franks&, would get appended to the end of the forwarding URL. This allowed me to pass form data to the thank you page.
I even tried adding the empty parameters to the forwarding URL e.g. thinking that it might be looking for them in the URL, which is not something I ever had to do in the previous iteration of the landing page builder. However, this did not seem to make a difference.
Has anyone else run into this issue?
Any advice would be greatly appreciated!