Fixed Footer Form Popup disappears on mobile versions when filled with text

Hello Webflowers out there,

Here is my site Read-Only: Webflow - Derigo Installations GmbH
(how to share your site Read-Only link)

Description:
i’ve got a Problem with a Modal (the blue one on the bottom of the 1st picture) , which is fixed on the bottom and only pops out if i scroll up. In Desktop Mode, this is working very fine, but on Mobiles ive’got the Problem that it disappears when i want to fill the form.

That’s not good, because the User is not going to see what he is writing on ipad and mobile

So please can you help me? The picture with the IPAD Screen is here so you can see what i mean:

Thank you in Advance & Best Regards from Austria