I have an Ender 3 Pro with a Bigtree SKR board. I just replaced the entire hot end (thermistor, heating element, Micro Swiss hotend).
Now when I try to print a Benchy everything seems fine until maybe the 3rd or 4th layer. Then the PLA stops flowing so I stop the print and the temperature flies back up from 220 to 260 °C on its own (I do not want to print at 260 °C, I want to print at 220 °C). This makes me assume the PLA is stopping because the temperature is too hot.
What would cause this? Did I wreck the thermistor when I was putting it in? Is it a firmware issue? Why isn't runaway protection turning it off?