Just to add my report, this occurs for me with 2.6.34.7-56.fc13.x86_64 in FC13.

/var/log/messages from plugin to attempted discovery:

Sep 24 10:22:37 lip06jcs-desktop kernel: usb 5-2: new full speed USB device using uhci_hcd
 and address 2
Sep 24 10:22:37 lip06jcs-desktop kernel: usb 5-2: New USB device found, idVendor=0a12, idP
roduct=0001
Sep 24 10:22:37 lip06jcs-desktop kernel: usb 5-2: New USB device strings: Mfr=0, Product=0
, SerialNumber=0
Sep 24 10:22:37 lip06jcs-desktop kernel: Bluetooth: Core ver 2.15
Sep 24 10:22:37 lip06jcs-desktop kernel: NET: Registered protocol family 31
Sep 24 10:22:37 lip06jcs-desktop kernel: Bluetooth: HCI device and connection manager initialized
Sep 24 10:22:37 lip06jcs-desktop kernel: Bluetooth: HCI socket layer initialized
Sep 24 10:22:38 lip06jcs-desktop kernel: Bluetooth: Generic Bluetooth USB driver ver 0.6
Sep 24 10:22:38 lip06jcs-desktop kernel: usbcore: registered new interface driver btusb
Sep 24 10:22:38 lip06jcs-desktop bluetoothd[27218]: Bluetooth daemon 4.64
Sep 24 10:22:38 lip06jcs-desktop bluetoothd[27219]: Starting SDP server
Sep 24 10:22:39 lip06jcs-desktop kernel: Bluetooth: L2CAP ver 2.14
Sep 24 10:22:39 lip06jcs-desktop kernel: Bluetooth: L2CAP socket layer initialized
Sep 24 10:22:39 lip06jcs-desktop bluetoothd[27219]: Parsing /etc/bluetooth/network.conf failed: No such file or directory
Sep 24 10:22:39 lip06jcs-desktop kernel: Bluetooth: BNEP (Ethernet Emulation) ver 1.3
Sep 24 10:22:39 lip06jcs-desktop kernel: Bluetooth: BNEP filters: protocol multicast
Sep 24 10:22:39 lip06jcs-desktop kernel: Bridge firewalling registered
Sep 24 10:22:39 lip06jcs-desktop bluetoothd[27219]: bridge pan0 created
Sep 24 10:22:39 lip06jcs-desktop bluetoothd[27219]: Parsing /etc/bluetooth/input.conf failed: No such file or directory
Sep 24 10:22:39 lip06jcs-desktop bluetoothd[27219]: Parsing /etc/bluetooth/audio.conf failed: No such file or directory
Sep 24 10:22:39 lip06jcs-desktop kernel: Bluetooth: SCO (Voice Link) ver 0.6
Sep 24 10:22:39 lip06jcs-desktop kernel: Bluetooth: SCO socket layer initialized
Sep 24 10:22:39 lip06jcs-desktop bluetoothd[27219]: HCI dev 0 registered
Sep 24 10:22:39 lip06jcs-desktop bluetoothd[27219]: HCI dev 0 up
Sep 24 10:22:39 lip06jcs-desktop bluetoothd[27219]: Starting security manager 0
Sep 24 10:22:39 lip06jcs-desktop bluetoothd[27219]: Parsing /etc/bluetooth/serial.conf failed: No such file or directory
Sep 24 10:22:39 lip06jcs-desktop kernel: Bluetooth: RFCOMM TTY layer initialized
Sep 24 10:22:39 lip06jcs-desktop bluetoothd[27219]: Adapter /org/bluez/27218/hci0 has been enabled
Sep 24 10:22:39 lip06jcs-desktop kernel: Bluetooth: RFCOMM socket layer initialized
Sep 24 10:22:39 lip06jcs-desktop kernel: Bluetooth: RFCOMM ver 1.11
Sep 24 10:22:39 lip06jcs-desktop NetworkManager[1312]: <warn> /sys/devices/virtual/net/pan0: couldn't determine device driver; ignoring...
Sep 24 10:22:44 lip06jcs-desktop bluetoothd[27219]: Sending read scan enable command failed: Connection timed out (110)
Sep 24 10:31:47 lip06jcs-desktop pulseaudio[2526]: ratelimit.c: 592 events suppressed
Sep 24 10:42:22 lip06jcs-desktop kernel: hci_cmd_task: hci0 command tx timeout
Sep 24 10:42:37 lip06jcs-desktop yum[28215]: Installed: bluez-libs-devel-4.64-1.fc13.x86_64
Sep 24 10:42:44 lip06jcs-desktop bluetoothd[27219]: Discovery session 0x7f0704de8b60 with :1.133 activated
Sep 24 10:42:44 lip06jcs-desktop kernel: hci_cmd_task: hci0 command tx timeout
Sep 24 10:43:27 lip06jcs-desktop bluetoothd[27219]: Stopping discovery
Sep 24 10:43:27 lip06jcs-desktop kernel: hci_cmd_task: hci0 command tx timeout

Last message repeats when I try to do anything else with the adapter.