My AirPods Pro no longer appear on Find My. Does that mean they might have been stolen and renamed?

My AirPods Pro have been lost for about a week. I've looked everywhere and tried to play a sound from them using Find My at a friend's house and at home. The last place to check would be my office, but before I could play a sound from them there, they suddenly disappeared from the Find My app. They also don't appear on iCloud. Does this mean they have been stolen or is there something wrong with Find My?