We have just had some students complaining about this on Samsung Galaxy Tab (chasing for versions) and confirmed it's still an issue on a Pixel 5 with Chrome.
Was there a ticket ever raised on this? Sorry, missed it in tracker if there was.
I don't remember if this was a specific bug, but I have not yet seen any reports like this with 3.9.x. You can try the latest version at https://qa.moodledemo.net/mod/quiz/view.php?id=31 if you want to try on these devices.