The post has music. The desktop says it doesn't.
You attach a track to a post. On the phone it's there, credited, tappable. Open the same post on a computer and the music simply isn't mentioned — same post, same account, one of the two clients forgot.
Attach music to a post. The phone shows it: the track name scrolling along the bottom, the artist credited, the audio page one tap away. Open that identical post in a desktop browser and the music is absent from the description of the post — not muted, not broken, just never mentioned. The attachment you deliberately made is invisible on the surface where you might actually be cataloguing your own work.
Which leaves you in the position of not being able to confirm, from your computer, whether the thing you attached is attached. The only way to check what your post contains is to pick up a different device.
The same root as a real case
This is the quiet version of case 032: Instagram’s desktop client isn’t a client, it’s a partial rendering of one. Case 032 is the part that costs measurable time — no seek bar, so you rewatch the whole reel to reach a moment. This one costs almost none, and is arguably worse, because it doesn’t waste your time so much as misinform you about your own content. A missing button is visible. Missing metadata looks exactly like metadata that was never there.
Two surfaces, one database, and no shared definition of what a post is.
Unverified which way it fails. Whether the desktop client drops the audio attribution from what it renders, or whether posting flows attach audio in a form desktop doesn’t read, changes who owns the fix — worth confirming against a post known to carry music before this is quoted as settled.