@hamiltonprops From re- reading your OP, you say that the temperature drops 20 degrees within a second or two. That would indicate it's not a "real" drop in temperature but rather a drop in the indicated (measured) temperature - unless your hot end has an insanely low thermal mass. So, yes I go for some sort of cross talk or electrical "noise". Are you sure you haven't got a bad crimp on the thermistor wiring somewhere?
3.3 v rail seems good , the SAM chip is getting a little hot , around 40 degrees , the esp is ice cold.
Just another thing I noticed , if I press the erase or reset button , nothing happens , no flashing of any LED's
The SAM shouldn't get hot if it's just waiting to be flashed. Perhaps it is faulty.
Once the chip is erased and waiting to be bootloaded, I wouldn't expect the Erase or Reset buttons to flash any LEDs.
It's possible in theory to program the processor via the PanelDue port (and for the same reason, having a PanelDue connected might interfere with programming over USB, although in practice it doesn't seem to). You would need Bossa or SAM-BA and a serial-to-UART converter with 3.3V signal levels.
That does sound like a problem with the WiFi module. It's possible in theory to set the Mac address in firmware, but we don't use that facility because each WiFi module is supposed to have a unique default address.