AirPods Pro (3rd gen) beeps while wireless charging

When I put my AirPods Pro (3rd gen) on the wireless charger pad they beep (it's more like a bell sound). This is normal and it is just to notify that they are starting to charge.

Now, after a while, they starting beeping roughly every 1 minute and 35 seconds. At the beginning, I thought there was a problem with the charging process and the AirPods where disconnecting / connecting from the wireless charger. However, I noticed the beeping starts once the earbuds are charged but the case is still charging. So this could be a feature to notify the user that the earbuds are already charged.

Could somebody confirm that this is intended and it is a feature in the AirPods Pro (3rd gen)? And if so, could the Apple team make a firmware update so they don't beep every 1 minute and 35 seconds constantly? I think it is a bit annoying that they keep beeping, specially at night. A better implementation would be beep once or twice. The user knows that the earbuds are charged but still needs to keep the AirPods in so the case is completely charged, too.