I never worked on a Tesla but I did work on GM electric cars for 10 years. When replacing battery cell sections in Volt cars, you have to balance the charge between the new section and the other 2 before reassembling the battery. There are temperature sensors in the cells and they don't like heat. I found if the battery was in direct sunlight the sensors would cause the control module to shut down the charge process. The first time this happened was quite a surprise to me and later I saw other guys struggling with the same problem so I graciously told them about it.

When the battery is in the car there is coolant flowing through it but it, and the inverter and motor are monitored for heat and power will be reduced or shut down if needed. I have no idea if that is what is happening in your scenario but I'm full of anecdotes.