Had this happen 7 hours into a print. Also happened after a few, few hour prints.
Not sure what’s causing yet but experimenting with different nozzles.
The extruder seems to keep trying to push, and the last time it happened, push the clips out and the fillament ended up spooling to the floor.
This is what it looks like after pulling apart the hotend and removing the nozzle. I was then able to push it through (I couldn’t pull it back out the way it came in).