I have Scrivener for Windows and IOS, I use the Baskerville Old Face font on my Windows Scrivener and recently imported the font to my iPad so the font would stay the same across my devices. I can use italics perfectly on the windows Scrivener, but as soon as I sync it to my iPad the italics disappears and it’s impossible to italicize text on the iPad. (Bold also doesn’t work, I can underline text though.)
It’s really irritating because I use italics and bold while working on a project so I’ll know what to edit in the future, and I can’t always remember what formatting I wanted later.
Did the font file you installed on iPad include both italic and bold styles? iOS won’t “fake” italics or bold; the fonts you install must include italic and bold styles in order for italics or bold to be available.
My understanding is that some fonts don’t support true italics. For these, Windows OS creates a simulated italic, but iOS does not.
I can’t say that’s what’s happening with your font, but it could be.
I use typewriter fonts, many of which don’t support italics, and see the same thing. Windows makes italics work somehow, but iOS doesn’t. After much frustration, I’ve moved to using underlining, which always seems to work, and during the compile process have Scrivener change the underlines to italics.