I've been using pellet cookers for 13 years.
6 years with my current FEPG 1000, 5 years with an FEC 100 and 2 years with a CS-570 during this time I've only had this one auger jam.
I've just reassembled my FEPG 10000 after clearing the jam.
To clear the jam I had to manually move the auger back and fourth multiple times to loosen the pellets and remove them.
The pellet bin was full of dry cookshack pellets and there was some accumulated dust in the bottom, I'm not sure if this was a lot of dust or not as I usually just top off the pellet bin.
I've no idea what might have caused the jam but I'd like to hear what others think.