Airpod setting "Enable Charging Case Sounds" is greyed - cannot turn off charging sounds

When I plug in my Airpod charging case (Pro, 2nd Gen) the case makes a beeping sound, not just initially but continuously.

In Settings, the "Enable Charging Case Sounds" shows green (on), but the setting itself is greyed and I cannot select it to turn it off.

I have tried removing the Airpods via Bluetooth and then setting them up again (holding down the case button 15 seconds and going through the setup routine). But this does not change the 'greyed out' state of this setting. Any ideas on what else I can try?