The heating "PNP NOR" gate shows a heat flow always if a transistor is conducting.
Simulate until T=200 s. Plot V1.v and V2.v and C2.v to see the NOR-functionality. High potential is -6V which means logic "true". Low potential is 0V which means logic "false".
To see which transistor is conducting one can have a look at the temperatures T1.heatPort.T and T2.heatPort.T and the heat flows T1.heatPort.Q_flow and T2.heatPort.Q_flow of the heatports of the transistors T1 and T2.
They are different from zero if the transistor is conducting.