[18 March 2023] Ok. I'm trying to print Tetent Concept3 and I've encountered the strange behaviour again:

So it seems that there's actually a zone between 180 and 220 degrees where the readings are not correct. 

However, it seems that (other than that one mystery hiccup at 115C), the temperature reading is fine if the hotend cools down to 45C.

Maybe some component is overheating and I should turn the internal fan on? Right now I've got an external fan pointed at the DP2's general direction and I'll see if I can make it though the rest of this 90 minute print.

[perhaps 3 minutes later] Well that didn't last long at all:

It seems that cooling down to 140C works too... 

Maybe the fan wasn't pointed precisely enough. I didn't want the part to warp or anything. I'm trying again with an even more directly pointed fan.

[23:07] Nouhhh my restarts are now proving ineffective!

[23:14] Okay alright pack it up guys. This print is a fail.