Random Temperatures and then Print Stops  

Random Temperatures and then Print Stops

So, I just had this issue with my printer today. I've been printing various PLA parts for the past week or so with no issues. I printed a part overnight, and I took the part off this morning. Then, I started another print of the same part. I didn't even remove the SD card, I just started the print again. Normally, the nozzle would heat up to 210, then it would go through the 9 calibration points, then it would go home and start the print. This time, the nozzle heated to 210, then it started doing the calibration points. Then, it started cooling down with the nozzle temp showing 210/0 (210 but cooling down to 0) and the bed showed 60/0 (60 but cooling down to 0). After it got done the calibration points, it went home. Then, the nozzle showed 170/210 and the bed showed 55/60 because during the calibration they had cooled a little, but now they were going back to their temperatures for print. So I decided to let it go and see what would happen. Well, the nozzle and bed both reached their temps, but it didn't start the print job. It just sat at home. However, the SD% started going up as if it was printing. And it went a lot faster than it normally would if it was printing. It's a 17 hour print, but it only took about a minute for SD% to reach 100%. After it reached 100%, the print job ended. The nozzle and bed went into cooldown and it said "Prusa i3 MK2 ready." as if it successfully printed a job.

I've done some troubleshooting and can't figure out the problem. I updated the firmware to 3.1.0 and that didn't fix the problem. If I go to my settings and just set the nozzle and bed temps to 210/60, they both hold their temperatures fine. I tried printing other files that I've successfully printed and they didn't work. I tried reslicing the files and that didn't work. I tried using a different SD card and that didn't work. I'm not really sure what would've caused it. It's weird that it would print one part fine, and then the very next part it starts doing this without any changes to any settings or files or anything.