Nope it's completely silent failure, only thing noticeable is I think if I toggle it on and off in the menu a few times it will freeze coming back on. But rebooting fixes it.

But yeah AirDrop wont work in the state so it's likely the same issue because on a long enough uptime the chip crashes without fail.

Don't know if you're aware, but if you click the bluetooth icon in the menu bar with Shift and Option held down, you get a debug menu that lets you reset the bluetooth module - might save you rebooting.