I use the E3D Revo extruder. There is no grinding on the filament. You know we can use M18 to disable all motors. I could be wrong but I am under the impression that during some print sessions, the extruder motor might have been disabled or not enough force was generated for it to keep the filament at the level it was supposed to be. For example, sometimes during those problematic print jobs, I could easily manually pulled filament out or easily pushed them in for the nozzle to extrude more. Could there be something wrong in the software? I recall that after I modifed the M600 position according to the following post, in the Update Manager I got a message about a file being not clean. I think I did a light fix option. Enclosed is the latest log.
Move out of range error when M600 was executed
klippy_strange_extrusion.zip (1.4 MB)