With one of the patches in the last week, a Bluetooth bug reappeared.

The symptom is that after a few minutes (anywhere from about 2 to as much as 15
minutes) the Bluetooth mouse stops working.  If I disable and re-enable
Bluetooth through the system tray icon, it will start working again for some
time.

This problem existed earlier in the year, but it was resolved several months
ago.

This might be bug 970195 showing up again.  The timing is about right.

lsusb output:
Bus 002 Device 004: ID 0a5c:5802 Broadcom Corp. BCM5880 Secure Applications
Processor with fingerprint touch sensor
Bus 002 Device 006: ID 8087:07dc Intel Corp. 
Bus 002 Device 002: ID 8087:8000 Intel Corp. 
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 056a:4001 Wacom Co., Ltd 
Bus 001 Device 003: ID 0c45:649d Microdia 
Bus 001 Device 002: ID 8087:8008 Intel Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 002: ID 0bc2:ab34 Seagate RSS LLC 
Bus 003 Device 004: ID 047f:0113 Plantronics, Inc. 
Bus 003 Device 005: ID 04e8:6860 Samsung Electronics Co., Ltd Galaxy (MTP)
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Output of bluetoothctl:
[NEW] Controller 7C:5C:F8:33:1C:0A Socrates [default]
[NEW] Device 00:1F:20:23:F3:E0 Logitech Bluetooth Mouse M555b

Relevant packages:
bluedevil5-5.8.0-1.1.x86_64
libQt5Bluetooth5-imports-5.7.0-1.1.x86_64
libQt5Bluetooth5-5.7.0-1.1.x86_64
libbluetooth3-5.42-1.1.x86_64
gnome-bluetooth-plugin-phone-manager-0.69-9.7.x86_64
gnome-bluetooth-3.20.0-1.2.x86_64
bluez-qt-udev-5.26.0-1.2.x86_64
bluez-5.42-1.1.x86_64
libgnome-bluetooth13-3.20.0-1.2.x86_64
libKF5BluezQt6-5.26.0-1.2.x86_64
typelib-1_0-GnomeBluetooth-1_0-3.20.0-1.2.x86_64
bluez-qt-imports-5.26.0-1.2.x86_64
pulseaudio-module-bluetooth-9.0-2.1.x86_64

Journalctl | grep blue recent info:
Oct 17 13:36:50 Socrates.i-pi.com kernel: input: Logitech Bluetooth Mouse M555b 
as
/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5/2-1.5:1.0/bluetooth/hci0/hci0
:256/0005:046D:B009.0005/input/input29
Oct 17 13:36:50 Socrates.i-pi.com kernel: hid-generic 0005:046D:B009.0005:
input
,hidraw1: BLUETOOTH HID v4.19 Mouse [Logitech Bluetooth Mouse M555b] on
7c:5c:f8
:33:1c:0a
Oct 17 13:44:37 Socrates.i-pi.com kernel: Bluetooth: hci0: turning off Intel
dev
ice LED failed (-19)
Oct 17 13:44:37 Socrates.i-pi.com bluetoothd[1859]: Endpoint unregistered:
sende
r=:1.34 path=/MediaEndpoint/A2DPSource
Oct 17 13:44:37 Socrates.i-pi.com bluetoothd[1859]: Endpoint unregistered:
sende
r=:1.34 path=/MediaEndpoint/A2DPSink
Oct 17 13:44:37 Socrates.i-pi.com systemd[1]: bluetooth.target: Unit not needed 
anymore. Stopping.
Oct 17 13:44:37 Socrates.i-pi.com systemd[1]: Stopped target Bluetooth.
Oct 17 13:44:37 Socrates.i-pi.com dbus[1837]: [system] Rejected send message, 6 
matched rules; type="error", sender=":1.34" (uid=1000 pid=2890
comm="/usr/bin/pu
lseaudio --start --log-target=syslog ") interface="(unset)" member="(unset)"
err
or name="org.bluez.MediaEndpoint1.Error.NotImplemented" requested_reply="0"
dest
ination=":1.4" (uid=0 pid=1859 comm="/usr/lib/bluetooth/bluetoothd ")
Oct 17 13:44:37 Socrates.i-pi.com dbus[1837]: [system] Rejected send message, 6 
matched rules; type="error", sender=":1.34" (uid=1000 pid=2890
comm="/usr/bin/pu
lseaudio --start --log-target=syslog ") interface="(unset)" member="(unset)"
err
or name="org.bluez.MediaEndpoint1.Error.NotImplemented" requested_reply="0"
dest
ination=":1.4" (uid=0 pid=1859 comm="/usr/lib/bluetooth/bluetoothd ")
Oct 17 13:44:37 Socrates.i-pi.com dbus[1837]: [system] Rejected send message, 6 
matched rules; type="error", sender=":1.34" (uid=1000 pid=2890
comm="/usr/bin/pulseaudio --start --log-target=syslog ") interface="(unset)"
member="(unset)" error name="org.bluez.MediaEndpoint1.Error.NotImplemented"
requested_reply="0" destination=":1.4" (uid=0 pid=1859
comm="/usr/lib/bluetooth/bluetoothd ")
Oct 17 13:44:37 Socrates.i-pi.com dbus[1837]: [system] Rejected send message, 6
matched rules; type="error", sender=":1.34" (uid=1000 pid=2890
comm="/usr/bin/pulseaudio --start --log-target=syslog ") interface="(unset)"
member="(unset)" error name="org.bluez.MediaEndpoint1.Error.NotImplemented"
requested_reply="0" destination=":1.4" (uid=0 pid=1859
comm="/usr/lib/bluetooth/bluetoothd ")
Oct 17 13:44:39 Socrates.i-pi.com kernel: Bluetooth: hci0: read Intel version:
3707100180012d0d00
Oct 17 13:44:39 Socrates.i-pi.com kernel: Bluetooth: hci0: Intel Bluetooth
firmware file: intel/ibt-hw-37.7.10-fw-1.80.1.2d.d.bseq
Oct 17 13:44:39 Socrates.i-pi.com kernel: Bluetooth: hci0: Intel Bluetooth
firmware patch completed and activated
Oct 17 13:44:39 Socrates.i-pi.com bluetoothd[1859]: Failed to obtain handles
for "Service Changed" characteristic
Oct 17 13:44:39 Socrates.i-pi.com bluetoothd[1859]: Sap driver initialization
failed.
Oct 17 13:44:39 Socrates.i-pi.com bluetoothd[1859]: sap-server: Operation not
permitted (1)
Oct 17 13:44:39 Socrates.i-pi.com bluetoothd[1859]: Endpoint registered:
sender=:1.34 path=/MediaEndpoint/A2DPSource
Oct 17 13:44:39 Socrates.i-pi.com bluetoothd[1859]: Endpoint registered:
sender=:1.34 path=/MediaEndpoint/A2DPSink
Oct 17 13:44:39 Socrates.i-pi.com systemd[1]: Reached target Bluetooth.
Oct 17 13:44:47 Socrates.i-pi.com NetworkManager[1856]: <info> 
[1476733487.1153] bluez: BT device Kenneth's Galaxy S6 (78:40:E4:A5:08:56)
added (NAP)
Oct 17 13:44:47 Socrates.i-pi.com NetworkManager[1856]: <info> 
[1476733487.1160] manager: (78:40:E4:A5:08:56): new Bluetooth device
(/org/freedesktop/NetworkManager/Devices/5)
Oct 17 13:44:47 Socrates.i-pi.com kernel: input: Logitech Bluetooth Mouse M555b
as
/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5/2-1.5:1.0/bluetooth/hci0/hci0:256/0005:046D:B009.0006/input/input30
Oct 17 13:44:47 Socrates.i-pi.com kernel: hid-generic 0005:046D:B009.0006:
input,hidraw1: BLUETOOTH HID v4.19 Mouse [Logitech Bluetooth Mouse M555b] on
7c:5c:f8:33:1c:0a