Noises coming from Extruder assembly

As my prints are going through, I head an occasional “Click”.
It is happening as the extruder is pushing material and not when it reverses to move.

Anyone have any ideas?

I had a sound like that, it turned out to be the reel of filament “climbing up” on the shoulder of the reel holder as it slowly turned, then dropping back down. It really mystified me until I just happened to be looking at it when it happened. That might not be it, but it’s something to watch for.

Mine clicks if the hobbed bolt nut is a little loose.