Battery drain overnight while shutdown

My internal contact replied to my email with "Customers should call into support and also file feedback hub item and share the link to it. " File a Feedback Hub problem report, get the shared link and post it here in a reply.

This would also seem to suggest that it's not actually a battery drain issue but rather poor calibration of the software reading the charge.  That's a less troubling problem, at least, but still very annoying and disappointing for MS's flagship devices. Regardless of what's going on I would very much like a fix.

Okay, new development (if anyone is even following this).

Check this out, supposedly I lost over 20% while my PC was shut down for less than 20 minutes... That's not possible! Not for a perfectly healthy battery that functions as expected for several hours when the PC is actually in use.

So it has to be that the battery isn't actually draining, the software is just reading its charge wrong, right?

I am having the same issue!

Here is a quick rundown of my problem.

7/6/19 I bought a Surface Pro 6 i7 1TB. This device turned out to have a defective screen so I took it in for a replacement on 7/27.

7/27/19 I am assigned (what I later discovered was a refurbished unit) a replacement unit. A few days after that I started to notice that when I leave it at 100% at night, unplug it, go to bed, and when I wake up in the morning it would only have 74% o 75% battery left! Also when it is 100% and I unplug it, take it with me to work, by the time I reach my office about 45 minutes later then turn it on it only has 74 to 75% battery left! I was able to observe this multiple times. I tried several troubleshooting steps to no success. I am not using hello cortana face unlock or anything fancy.

8/15/19 I went to a Microsoft Store to ask them to take a look at the battery drain issue, and they said they saw nothing wrong and suggested I factory reset the unit which I did when I got home! But the following day the same issue appeared! 

8/16/19 I went back to the Microsoft Store and told them the issue has not gone away. They issued me a brand new Surface replacement. At last I thought that was the end of the issue. I left the unit charging overnight, and this morning it was showing 100%. Out of curiosity I wanted to find out if this unit would have the same issue so I turned off the device at 100%, unplugged it, then left it for a couple of hours. When I turned it back on the battery was showing 74%!!

At this point I don't even know what to do. If anyone has a solution to this problem please share, otherwise I have no choice but to make another trip to the Microsoft Store for a possible fourth replacement.

Here is the drop observed this morning - 

My entire battery report is below: