***EDIT NOTE: The thermal stack bug is present anytime you split a stack, it's not just for rails.
SO! There is a bug where the stack that is loaded into a conveyor that calculates the heat of the last packet as if it contained the original full mass of the stack.
Preheated pills to 135.5c and 135.6c. The first packets in the conveyor are converted to 19.9c and the last retains the original temperature.
The first, middle, and last 20kg pill packets and the control 10