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Weird charging behavior occasionally, cant explain it.

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So we picked up a Model 3 Performance in December. Since we bought it something weird has happened maybe 5-7 times when charging at home. I charge to 90% every day at home, when I get the charge complete message from the Tesla App I unplug it because we also have to charge our Model S. The weird part is Model 3 continues to charge and the percentage/miles increase even though it is already unplugged!!
The increase has ranged anywhere from 3 miles to 10 miles. I can't replicate it and don't see any particular pattern when it happens. My charging set up at home is a 14-50 outlet with my UMC plugged into it. This behavior has occurred using our UMC 1 from our Model S charging at 40A and also our UMC 2 from the Model 3 charging at 32A. Its happened on various software versions too. No error messages in the car or error lights on either the UMC1 or UMC2. This has only happened when charging at home, has never happened when using a Supercharger.
This happen to anyone else? Can anyone explain why this happens? Should I have Tesla check it?
Car is great other than my 90% dropping from 264 miles new to 253 miles now.
 
I've seen the percentage (I recommend not using mileage ever as it causes too much stress. If you need mileage to empty, refer to the energy app which is based on your driving habits) go up and down by as much as 3% just like you. I attribute this to the BMS doing recalculations as the battery and external temperatures warm and cool. Remember, that mileage is just an estimate of reading the average voltage across over 4400 individual cells and that measurement is not exact. Voltage fluctuates with temperature (technically it's the internal resistance but V=IR) hence the slight variation.
 
You don't see the display actually say it's charging, though, right? You just see the rated miles go up by a few? That would be pretty normal, because the car's estimation of the energy in the battery pack does figure in the temperature some. So even after charging is complete if the temperature of the pack continues to drift a little bit, you might see the miles number move a bit more by some usually small single digit number.
 
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