Modal with locked footer works on Android, but not iPhone

Not sure who’s around, but I just finished this mobile prototype. It’s work fine on Android, but not iPhone.

The modal has a fixed (not exactly sticky) footer if you click on +16 from the home page. The scroll works fine on Android but will not scroll on iPhone.

I can provided the rp file if anyone can help, or if there are any thoughts on what the issue may be.