I was printing a part which held a captive nut in a hollow void, so I needed to insert a pause in the gcode to interrupt the print.
The printer reached this line, paused correctly, but after continuing the print from the printer's control, it crashed the rest of the system, stopping all other prints attached to the Pi.
I tried to recover this print a few times, and each time the system would crash at M117; M601. I could still see the GUI on the webpage, but it wasn't displaying the machines, and things were generally unresponsive.
I just worked around this for now, but figured it was repeatable enough to mention. Thanks