Dell Precision 7740 shuts down but power light stays on?

I have a Precision 7740 that's about a year out of warranty.  I haven't used it in a couple weeks, and this morning when I pulled it out of the case, I noticed the power light was on.  The keyboard was dark, as was the screen, but the power light was on.  As far as I KNOW, when I last used it, I shut it down normally.

I attempted to boot it, but nothing happened, so I presumed the battery was dead.  Plugged it in, booted it normally, and everything appears normal.  Shut it down and the power light stayed on.

I searched for this condition but only found a 2020 topic that appeared to be similar, but nothing was posted for a solution.  It just said someone would contact the person by pm...  Not very useful to everyone else.  I found computers that wouldn't shut down and computers that would start on their own, but nothing else for a computer that appears to shut down normally but doesn't turn off the power light.

I also tried the thing where you press the "D", then power, then release the "D" and there was a lot of red, green, blue, white screen flashing, then it rebooted.  I have no idea WHAT I was supposed to learn from that.

I've shut it down and rebooted it several times, and it appears to boot normally and shut down normally, but the light is on.  I also tried holding down the power button for 30 seconds.  One time it just booted, another time it appeared not to boot, but in both cases the power light stayed on.

When I attempted to reboot after the long power button hold, it made me reset the date and time.  But, since then it has continued to boot and shut down normally EXCEPT the power light stays on.

As far as I know, there has not been ANYTHING changed in hardware or software in a number of months except the normal Windows 11 updates.  I ran Support Assist and it did a BIOS update, but nothing else found anything.

This doesn't appear to impact usage - the laptop seems fine.  But, it's not normal and I presume over a few weeks it would completely drain the battery.

How do I fix this?