Showed a couple of odd symptoms - seemed to be less than fully charged a couple of times over a week or so, then wouldn't charge.
Low voltage (battery shaped light) and high voltage (!) warning lights on dash.
Car still drives fine, 12v battery seemed to have a good charge.
One other idea is that the pack has a defective cell. The "less-than-full" charging is one of the indicators for that issue. A MUT3 scan of the pack would show the max and min cell voltages--if a cell is lower than all the rest then it will cause the gauge to show less than full after a normal charge session.
i would hope that they tested the 12V while under load, or by specific gravity measurement, to get a real determination of health. A weak, old, or worn out 12V will cause a multitude of unrelated issues and problems in these cars.