We have a couple of TC-08 units. I have noticed that if a thermocouple is un-plugged and then replaced the the readings for that thermocouple change. Best viewed using the graphing, you see the trace go off screen when it is un-plugged (what you would expect) and then the indicated temperature is below what it was before the un-plugging. Only checked this at around 20°C but at this temperature it common to see the post un-plugging figure to be 0.5°C below the pre un-plugging figure. Any ideas why this might be happening.
FYI - the thermocouples are in a stable environment (water bath) and the computer is a laptop running off battery.