i do, and i have, but given the op's once a month takedown policy i'd assumed he'd have known that too.
looks like the COL isn't engaging the cam, hard to tell how worn it is from the pic byt it's worth checking that by hand.
pull everything bar the COL and the sector gear, rotate by hand and see if it's still moving.
normally this is pretty common if the COL is a different brand to the rest of the gearbox, but can also happen with wear.