This has happened to me twice during a long print
The z axis motors start to click...basically they are moving slightly up and down... When i paused the machine the click was still present
I killed the print job the z motors are still clicking...then i tried to home the machine. the homing only moved maybe mm then stopped did not reach the home switch....the only way to correct this was to turn off the R2C2 controller .....obviously the printed part was scrap.....I think this is a bug in the firmware but have no idea what is causing it
Any ideas