Checkout process different on Chrome vs Safari on mobile

Hi group,

I got a problem with the checkout page/process on my client's website (mobile mode). Whenever I place an order on Safari, everything goes smoothly except for step 3: 
Step 1: Email address
Step 2: Accepting the custom "Acknowledgement and risks form"
Step 3: Shows the order summary for 2sec, and then it scrolls back up automatically for the payment information + billing address

But, on Chrome, it's another game! Each of the steps starts by showing the order summary and are all mixed up.
Step 1: Shows the order summary and then scroll down to accept the custom form
Step 2: Shows the order summary, then scroll back up to enter the email and accepting the form (again)
Step 3: Shows the order summary and scroll up to fill the payment information + billing address

Also, buttons are black on Safari even though I personalized it to green. In Chrome, the buttons are green. Strange!

I asked the Squarespace support, but they told me they couldn't do anything... Any of you experiencing the same problem or could give me some answers on why is it happening?

website: https://snail-ray-daxz.squarespace.com/
pass: freelance