How can I get ligatures of IPA tone letters (which I presume to be OpenType ligatures) to display properly in Firefox (for Android, Samsung Galaxy S8)? Example: view the text pʰɪŋ˨˩ (an IPA representation of a particular Cantonese word). For the tone Google Chrome displays the intended form (a low-and-falling stroke meeting the bottom of a vertical bar), but Firefox displays a fallback, disconnected rendering (a low horizontal line meeting one vertical bar near the bottom, then another meeting a second bar at the very bottom). I assume this rendering bug affects other ligatures as well, but personally I'm most concerned with these tone letters for phonetic transcription.