Flutter Mobile Web Material Icons

This is not an issue involving getting Material Icons to display on web but rather an issue getting Material Icons & fonts to display on mobile web.

I have included the following in my pubspec.yaml file

uses-material-design: true

fonts:
    - family: Roboto
      fonts:
        - asset: assets/fonts/Roboto-Medium.ttf

In addition, I have dropped the ttf files for both fonts in the project's assets/fonts folder. When I run this using chrome, it works fine! However, when running this on an iPad pro in either Safari or Chrome, I get Times New Roman font and strange emojis in place of where the Material Icons should be.

I have verified that my fontmanifest.json file includes:

   {
        "family": "Roboto",
        "fonts": [
            {
                "asset": "assets/fonts/Roboto-Medium.ttf"
            }
        ]
    }, 
    {
        "family": "MaterialIcons",
        "fonts": [
            {
                "asset": "assets/fonts/MaterialIcons-Regular.ttf"
            }
        ]
    }

I am stumped. What is going on here?