Pretty common problem lately.......most likely its a worn A/R assist pawl. BNT 2404
Check the tips of each wing.....you'll know what I'm talking about when you see it. If its worn just a tiny amount it will make noise. If its not worn, then try bending the wings in so it holds on tighter to the ratchet disk it rides on. Like this /\ not too much though, as it will cause the reel to feel tight on the retrieve.Some will say the reel doesn't need the part, but I like to keep em in. They don't cost much. And they will help extend the life of that new A/R bearing you guys put in. Good luck.
Link to schematic.