Octopus Max not working with EZ31865

I'm using an Octopus Max with the EZ31865 designed for it. With the EZ31865 on Motor8 slot connected to a PT1000 and everything configured correctly in klipper it works just fine and reports the correct temps. The problem is after a print has started, as soon as the part cooling fan connected to Fan1 kicks on it causes the ez31865 to error out with "mcu 'mcu' shutdown: thermocouple reader fault"
I can trigger the fault at any time by starting the part cooling fan. Even worse if Fan1 is running at 100% there is no problem. It only triggers the fault if Fan1 power is between 0 and 100%.

Reproduce the fault with an EZ31865 on Motor8, a PT1000, and Fan1 at partial power. Then inspect the repository for the thermocouple-reader and fan-control entry points; done means Fan1 operation across its power range no longer causes the thermocouple reader fault.

Written by the indexing model from the issue text.