I was originally going to file an AnkiDroid bug but found that the issue exists on the Mac desktop version of Anki (version 24.11) as well.
Basically, if a card is scrollable and has audio buttons on it, the audio buttons do not scroll with the rest of the card. I have screen recordings of the behavior, but “new users can not upload attachments”.
This is an issue with your template, not a bug with Anki or AnkiDroid (you seem to be using a template made from someone else. Maybe report the bug there, too).
If you change the css from fixed to absolute position, then it works:
Ah, good call! Thank you! Yes, it is somebody else’s template. I’ve not looked into how Anki cards are made with HTML, so it hadn’t even crossed my mind that it might be an issue with CSS.