Upgraded to 24.04 COSMIC Alpha 5
Mar 03 17:32:06 sparkle kernel: Bluetooth: hci0: Opcode 0x0c1a failed: -19
Mar 03 17:32:06 sparkle kernel: Bluetooth: hci0: Error when powering off device on rfkill (-19)
Mar 03 17:32:06 sparkle kernel: Bluetooth: hci0: sending frame failed (-19)
Mar 03 17:32:06 sparkle kernel: Bluetooth: hci0: HCI reset during shutdown failed
I tried modprobe -r a bunch of modules and re-adding them but that didn't work. I also attempted many things noted in the Arch wiki.
I had no Bluetooth problems with 22.04.
Not sure yet if it reliably reproduces. I will report back.