I have no experience with the M1, but FWIW I would certainly not be surprised if the internal temperature of any component incorporating sophisticated digital signal processing varied significantly depending on what the DSP is being asked to do. In other words, on sample rate, filter selection, input format, etc.
Similar to how the temperature of the CPU chip in a computer varies widely as a function of its workload, resulting in its cooling fan audibly speeding up and slowing down at various times.
And of course the internal temperature will be directly affected by the room temperature as well.
Regards,
-- Al