Hi Rees,
Thank you for reporting the issue.
I only had an iphone SE at disposal at the moment, but I was not able to replicate the issue unfortunately. I also tried browserstack for a real-time 6S emulator, but no luck either: https://youtu.be/vgZ-QjeLFkk
Did a bit of investigation in the code as well, but I am not sure what might be the cause, and why I cannot replicate it. Can you try clearing the phone browser cache, maybe updating if neccessary?
I have no clue yet, what the issue is unfortunately.