I came over a font bug (I think) in iOS, as follows:
We use the font Amiri on a web site where we, in good classical tradition, set authors’ names in references in Sᴍᴀʟʟᴄᴀᴘs (in the css). Amiri doesn’t have smallcaps, so the browser simply downscales the font instead. This works fine under both MacOS and Windows as well as on Android platforms—but not on iOS (12.1). There, the lower ASCII characters are displayed correctly, but letters containing additional diacritics, such as Ā, Ḍ, Ḫ, etc., end up as being represented by <! > (exclamation mark followed by a space).
Has anyone else come across a similar problem, and could give me a clue as to why this happens, what could be a possible workaround (other than using another font, which unfortunately is not really an option), and/or who else I could contact with this issue?