This seems to happen every now and then:

Unexpected local ID: expected 32: WRTE, 15, 28, 'Broadcast completed: result=0\r\n'
_bot.1.zip/bot_code/bot_main.py", line 192, in _call_hook
ret = hook(botobj, *args)
File "swarming_bot.1.zip/config/bot_config.py", line 106, in hook
return func(*args, **kwargs)
File "swarming_bot.1.zip/config/bot_config.py", line 1164, in on_after_task
bot, True, devices, reboot=reboot)
File "swarming_bot.1.zip/config/bot_config.py", line 815, in _android_cleanup_throttle
return [p for p in parallel.pmap(fn, devices) if p]
File "swarming_bot.1.zip/adb/contrib/parallel.py", line 50, in pmap
return _pmap(_POOL, _QUEUE_IN, _QUEUE_OUT, fn, items)
File "swarming_bot.1.zip/adb/contrib/parallel.py", line 91, in _run
result = fn(item)
File "swarming_bot.1.zip/config/bot_config.py", line 814, in fn
low_power, unroot=unroot)
File "swarming_bot.1.zip/config/bot_config.py", line 778, in _android_device_cleanup_throttle
error = _android_device_ensure_watchdog(device)
File "swarming_bot.1.zip/config/bot_config.py", line 609, in _android_device_ensure_watchdog
if not device.Root():
File "swarming_bot.1.zip/adb/contrib/high.py", line 464, in Root
return self._device.Root()
File "swarming_bot.1.zip/adb/contrib/adb_commands_safe.py", line 536, in Root
if self._adb_cmd and self._Root():
File "swarming_bot.1.zip/adb/contrib/adb_commands_safe.py", line 620, in _Root
out = self._adb_cmd.Root()
File "swarming_bot.1.zip/adb/adb_commands.py", line 201, in Root
return self.conn.Command(service='root')
File "swarming_bot.1.zip/adb/adb_protocol.py", line 483, in Command
timeout_ms))
File "swarming_bot.1.zip/adb/adb_protocol.py", line 479, in StreamingCommand
return self.Open('%s:%s' % (service, command), timeout_ms).__iter__()
File "swarming_bot.1.zip/adb/adb_protocol.py", line 452, in Open
conn._OnRead(msg)
File "swarming_bot.1.zip/adb/adb_protocol.py", line 330, in _OnRead
'Unexpected local ID: expected %d' % self._local_id, message)
InvalidResponseError: Unexpected local ID: expected 32: WRTE, 15, 28, 'Broadcast completed: result=0\r\n'