Plastic part found in Hotend. Where does it belong? (K2 Pro)

Hi there. After inserting a new Nozzle, my filament got stuck, I opened the Hotend and found this part of plastic in there. The printer seems to work still fine (including CFS) but I assume that should be somewhere else. Any clue? (I think at the hole the filament should go through

I think this is the part on the bottom close to the cutter, you can slide it in there.