Section Collapse not showing up correctly when tapped on mobile device

Why doesn't this collapse work properly, am I missing something or is this just the way it performs?  

They way I see it, upon tapping the form collapse it should hop to the top of screen & open the (in my case) a text field below but it's all over, jumping & dancing around.

Why is this?

Form https://form.jotformeu.com/80222779185361

Pls see video

The form is embedded on a website based on your video. I've found the form here https://kidmov.uk/faq.html. I checked the form on my iPhone 6+ device, and I cannot seem to reproduce the problem. You are using the iframe method which is our recommended embed method for issues like this. Are you all set now? If not, please re-embed the form using our default embed method. See if that helps.