It is not a bug, it a new safety feature for old battery packs. Tesla discovered a certain condition in older batteries that could in very rare cases cause a fire. When the battery is at aprox 80% or higher, the car will take extra action to cool it down and run the coolant pump extensively. Running the coolant pump will prevent single cells that have this condition, to heat up and cause a fire. It is most likely dendrites that form inside the battery. It is most dangerous at high state of charge. That's why, when the battery is 80% or higher, the coolant pump runs just out of being extra careful.
Some batteries have developed this condition to a higher extend and as a safety measure Tesla has locked their top 10-15% out. IOW the car will not fully charge any more to avoid going to the highest state of charge. The car still shows 100% but the range is less. This is all part of the #batterygate issue.
If you have the problem at lower battery levels it might be that there are temperature differences within your battery that the car is trying to even out by circulating the coolant.