So newest data point: I put about 35-40 miles on it yesterday, brought it home, let it cool down, and then put the charger on it. (Standard mode, 120V, 15A on the yellow cable) This morning the display shows "Done Charging" and the port has blue light. (I think this means the charge was not interupted) The ideal range is now 101 and the battery icon looks like its at about 57%. So it appears this issue is getting worse as time goes on. Unless I'm misreading something... The plan is to leave it plugged in for the next couple of days and see if the wake up cycles balance the battery and bring up the ideal range.
I suggest you look at the ESS screen in the little diagnostics menu (1050 code). See what it shows for SOC%, MIN% and MAX%. If you have a big difference between MIN% and MAX% (more than 3% or so), your battery is out of balance and is the cause of the issue. The car's discharge (drive) is limited by MIN% (the brick with the lowest voltage), and the car's charge is limited by MAX% (the brick with the highest voltage). I suspect that this is your problem, and Gruber will be able to tell from the logs. My guess is that you will see MAX% in the high 80's%, after a standard charge that stops, and MIN% in the 50's%.
If the issue is simply that it is out of balance, then leaving it plugged into the charger after a full charge may help. But you will need to leave it there for hours/days. It can only re-balance a couple of percent a day.
However, the symptom you show, of the charge stopping earlier and earlier each time you drive/charge, is more likely to be caused by one or more bad bricks in the battery. Gruber can help you with that, while Tesla won't be able to do much.