@Phaedrux that's a quite likely cause. I didn't have a part fan for a good while and I added one more or less at the same time this started to happen. I had a silicon sock on, but I took a quick look and it has a big hole in the side, next to where the parts fan blows.
Actually, I have to upgrade the part fan to a more powerful one I bought. I will upgrade it and have it blowing at full speed, if that's the cause then the problem will show up more often. Thank you!

I think you're right, I remember reading something related to a heater fault in the console. I will pay more attention the next time the issue appears. Why do you think that it could happen?

Hi,

I'm experiencing an odd behaviour with my Duet WiFi 1.02 Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 2.05.1 (2020-02-09b1).
I have dual extruders but I print with only one of them most of the times. I slice with Simplify3D.
Sometimes the tool is "deactivated" mid print so the printer keeps working with no tool selected. I get errors in the console but as you can expect, no plastic is extruded and the entire thing fails.
I know is not the slicer because I re tried the same file and it completes. It happens randomly and not often, but when it happens, it might ruin a 20hs print.
I experienced it for the first time when I upgraded to RepRapFirmware 3. It was happening quite often so I downgraded back to stable version 2. Now it happens still though more sporadically. Ideally, it would not happen at all. I wonder if anybody experienced/resolved a similar problem before.

Thanks!