Apple provides HTML Embeds for Music Kit JS, as mentioned here.
There is a tool here that you can use to create embeds.
Scroll to Preview Player.
Now, if you set your browser width to less than 490 (right when the thumbnail gets smaller), the player will move vertically if you drag up. Not by much, it's hard to see without a contrasting background.. It's more noticeable in dark mode, as a white background shows clearly, like this:
I'm misusing "drag" here: a simple, vertical scroll will cause this.
Since this happens on Apple's own site, I'm fairly certain that this is not a "me problem," but who knows!
Anyhow, I'm not sure if anyone has come across this. These embeds are pretty handy, and I'm loathe to roll my own player just to fix this.
Any constructive advice would be appreciated.
Our engineering teams need to investigate this issue, as resolution may involve changes to Apple's software. I'd greatly appreciate it if you could open a bug report, include sources so they can see how you're calling MusicKit JS, and post the FB number here once you do.
Bug Reporting: How and Why? has tips on creating your bug report.