I've experienced this issue on my last two prints, and I have yet to figure out a solution. For reference, the print has roughly a 40 hr run time so i'm setting it up in the morning and monitoring it throughout the workday. The printing done while I'm there has been better than expected, which is why i'm confused as to why this is continuing to occur. I came in this morning after letting it run through the night and there was what looked to be a nest of filament, and the heating board had been knocked out of the mounting clips and was dangling in front of the 3D printer. When I checked the display on the printer it was showing a thermal runaway error. So far I've replaced the nozzle, but that did not seem to help. Any suggestions would be much appreciated.