Surface Book 2 battery drain whilst off

The Intel Magement Engine Interface (IMEI) can't be disabled for stability and eficiency purposes,. You solved your battery drain updating your firmware and shuting down your device using the shift key because you are telling to your OS to avoid the use of the fast boot and hybrid shutdown. 

Here is an image showing the block diagram of IMEI on a computer.

https://software.intel.com/content/www/us/en/develop/articles/getting-started-with-intel-active-management-technology-amt.html?wapkw=intel%20management%20engine%20interface

So I tested it last night, I updated my drivers manually from the MS website. I disabled, as mentioned above inboxerror2010, the Intel Management Engine Interface from the device manager, and I pressed shift, and I also shut down mentioned by Cesar Armando... ONE of these things fixed it. Tonight I will try only the shift + shutdown option to see if this fixed it. The problem with this bug is that I can only test it once a day since I use my device every day for work purposes.  I'll keep you guys updated with which one fixed it.

Thank you for your reply: I will definitely try your suggestions. And don't worry about your English: it's better than mine.

You can check if are problems with the performance of your power consumption with the comand powercfg /energy on powershell. To do this test you need to reboot your computer, login and leave your pc without programs opened. This procedure are important because if you have aplications opened you might have bad results in the report.

I have almost 3 years with my surface book 2 and I can see the batteries change te amount of energy they can hold on every charge. You can see these variation ejecuting the command powercfg /batteryreport. In the report you can see the charging variation over the time. Maybe these 4% droped after almost 24 hours off are only variations on the reporting mecanism of charge levels. 

Sorry if my english isn't good.

I have tried with your suggestion, but unfortunately to no avail. Yesterday around 23:55 I held the shift button while clicking on the "shutdown" command. I have just turned the Surface on, and launched the battery report. The battery loss is around 4% over almost 24 hours:

I will try with the other suggestions, namely the file integrity and the fix proposed by inboxerror2010. At this point, I have nothing (more) to lose.