iOS In-app browser does not render epub

[neurofoo]

The in-app browser does not render epubs in iOS. There are no issues with Android.

Expected behavior

• Go to the following link in iOS in-app browser and see the epub render
• https://futurepress.github.io/epubjs-reader/#epubcfi(/6/228[xchapter_108]!/4/2/2/2/1:0)

We've confirmed that the above link works and renders properly in Safari and Chrome (outside of the Phantom in-app browser).

[neurofoo]

On more digging, it seems like the expected iframe isn't even showing up in the DOM. Is this expected behavior or not?