Airpods showing up in my Apple ID?

Hiya all,

So earlier, I was going through my iCloud/Settings on my iPhone, and I found on the list of devices linked to my Apple ID including (ostensibly) my brother's AirPods? They have never shown up on that list before as understandably, they are linked to my brother's phone (and normally it just says my phone and my computer there), and from what I have googled, they aren't typically supposed to?

I tried several times to remove them from from the devices list, and my phone wouldn't do it until I rebooted my phone. I haven't had any security notifications/notifications about a new device being added to my Apple ID either, and so understandably, I am a little bit confused about what has happened and why? I have changed my password just to be safe anyway, but am wondering if anyone can explain what is going on, and if I should be concerned at all?

Thanks :)