I might have some technical info that explains this at least in part.
There are three coolant pumps in the Model S/X. Two for the battery, one for the drive train (motor/inverter). The reason there are two for the battery is that there are several valves that can redirect the coolant through the radiator or bypass, through the AC chiller or bypass and there is a combination where the loop is divided into to two strings, thus there needs to be two pumps to keep the fluid in motion.
I have seen the pump going on for hours or intermittently in my S many times. Unless there is a fan blowing at the same time, the intent to run the pump is not to cool the battery. With a battery that large, different sections of the battery can have different temperatures. Since internal resistance depends on temperature, a warmer battery will have lower losses than a cooler one. If individual cells in the pack operate at different temperatures, it eventually causes them to be charged and discharged slightly different from each other. The BMS will counteract to this by balancing the cell blocks. But of course you always want to have all cells to have the same temperature. If they are different, running the coolant will help even out those differences. This is why the coolant pump keeps running at random times.
10 hours of running the pump seems excessive. I bet this was caused by a bug in the software. Even large differences in temperature will be gone within an hour or running the pump.
Here is a screen shot showing the different cell blocks and the temperature difference between them.
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