Battery drain overnight while shutdown

Well Barb, Jason may have a point which I forgot.  Different Insiders are getting different builds.  I am on the fast ring myself and mine, probably did come with it baked in.  There is no record of the firmware being updated but yet I have the newer version.

No updates came across before or after the latest Build.  There is no record of it and I watch closely of the Windows Update panel for a list of those.

As you mentioned before, Firmware updates "DID" install separately and in fact I would see those which causes the system to require a reboot before the Insider build would download.  Not the case here and I may be getting this different build series which may explain the sub-letters of the Build number.  I kept wondering what those where because Microsoft remain "MUM" on everything.

I am getting a different build.  It is the only thing that explains it.

When I used to program in the past, I used to do the same thing to incorporate new code if it became available before compiling the program.  It reduces the deployment time but you do lose track of changes.  Microsoft probably has these catalog in a fashion to track them.

Right now, I have the machine turned off and unplugged.  It went down to 84% and am looking to see if it stays at that same level when I fire it up again later tonight.  If it does, we may finally have a fix to the power management system.  It is not important to myself since the machine is only used for the Insider Build testing and playing Age of Empires DE on it.  I do have it configured for regular use but don't use it.  I am keeping my Pro 3 RTM so that I can compare between the two.

But as for the updates, nothing else came across to include any automatic updates in the background.  I can always spot those because the machine slows down when they come across and a Firmware update requires a reboot.

Surface cannot check code into winmain for any build, they have their own separate maintenance and build/test/testdeploy/deploy thing. 

You provided a screen shot which clearly showed separate firmware. This wouldn't happen if it was baked in. Where and when it downloaded in the background separately is something I do not know, but I suspect that after the build itself downloads and while it is in the preparing stages, other downloads might be happening. Why you didn't see evidence of this isn't anything I can answer. But if you elect to believe Jason (source of truth as far as I am concerned), then there is a BUG you should file using the FBH stating that a firmware update was deployed at some point but never listed on the Updates Available Page or the Pending list.

There is a possibility that it is coming across during the setup process during the reboot of the build download.  It never shows what is downloaded.

Now Jason is correct - there are separate builds for Insiders for which is one point I forgot about.  There are different builds going out to Insiders and not every Insider is getting the same one.  I kept noticing a "VB" sub-letter with a number associated with the Build which is probably their tracking system for these builds.

Who knows.  Microsoft never talks to anybody about anything.

The important thing is that this particular firmware update just may be the "FIX".  It is too early to tell yet and I am going to test the heck out of it.  Right now, the machine is off and will be firing back up later tonight.  In fact, I am going to run Age of Empires DE on it while on battery to see how much of a drain it causes.

Let us wait and see.  As I mentioned before that this has been a really good thread and maybe we are seeing an end to the power problems these machine constantly have.  Really interested on the AMD flavors of the newer Pro 7 will have and AMD has been good with power management in the past (laptops, that is).  I might even get on.

Vb = vibranium https://www.thurrott.com/windows/windows-10/190138/windows-10s-next-major-updates-will-be-codenamed-vanadium-vibranium