Thinkpad S540 possible BIOS bug concerning WOL

Question

I have had a Thinkpad S540 for a few months, and have it installed as dual boot Windows 8.1 and arch linux.  After completely shutting the machine down from linux I found that the battery would be down to around 70% charge after three days unused, and decided to investigate this problem since it was not reasonable for a new battery to lose charge at anything like this rate.
By chance I came across a piece of information concerning the issue of disabling WOL (Wake on LAN) on the network interface, since I had seen one report that by default WOL is enabled and this requires power to be going to the network interface even when shut down in order to be able to respond to magic packets to start the machine up when it is shut down.
First I checked the BIOS WOL setting and found it was set to "AC only" by default. So I changed it to disabled. This machine has the latest available BIOS version 1.54.
However on investigating this after rebooting in linux I found that 
# cat /sys/class/net/enp3s0/device/power/wakeup
enabled
# ethtool enp3s0 | grep Wake-on
Supports Wake-on: pumbg
Wake-on: g
So WOL was still enabled despite it being set to disabled in the BIOS!
I learned that I can make sure that in arch linux the WOL setting can be changed to set to disabled after bootup by using a udev rule:
# cat 70-disable_wol.rules
ACTION=="add", SUBSYSTEM=="net", KERNEL=="enp3s0", RUN+="/usr/bin/ethtool -s enp3s0 wol d"
Then rebooting the machine I checked the WOL setting and it really is disabled now:
# ethtool enp3s0 | grep Wake-on
Supports Wake-on: pumbg
Wake-on: d
# cat /sys/class/net/enp3s0/device/power/wakeup
disabled
So I then ensured that the battery was 100% charged and shut down the machine and left it two and a half days - rebooting this morning the battery was still at 100% charge and no longer discharges unnecessarily when the machine is switched off,  so this is a clear indication of a bug in the BIOS for the WOL setting - it is still enabled despite the BIOS saying it is disabled!
How do I report this to Lenovo so that they can fix the BIOS and release a new one that is working?
I am aware of other users with different Thinkpads who seem to have the same problem, so this may be more widespread an issue than just on the S540.  
It is also not just an issue with the battery running down when fully shut down but will likely also be a problem for a machine in suspend mode since the network interface may be consuming a watt or so of power when in suspend, which will again run the battery down at an unacceptable rate.
I cannot imagine any use case where it would be necessary to have WOL enabled on a laptop that is mostly going to be used mobile - so having the default setting to AC only enabled, and having a BIOS bug enabling it when it is explicitely disabled is a serious problem.

Answer 1

Anyone running windows in the same laptop can check the same issue of battery drain due to WOl being enabled by default - in the Device Manager under the network card, opening the settings menu for the ethernet wired card the default for Wake-on-LAN on my computer was set to enabled. This can be changed to disabled, and you may need to also disable the setting for Wake on Magic Packet. Also in the Power Management tab it is possible to uncheck the settings for "Allow this device to wake the computer" and "Only allow a magic packet to wake the computer"
In my laptop these were all set to enabled by default.