Broken Encoder Gear - XDJ1000MK2

So I noticed the jog wheel on my XDJ1000MK2 was feeling crunchy and I could hear something rattling around in it. Decided to take it apart and found that one of the gears had fallen out: Item No. 9 and 19. I cant for the life of me figure out what it's purpose is though. Both Gear A and B engage with the jogwheel. I reassembled it without Gear B or the spring, and it seems to function completely fine. There is no notable difference or lack of functionality between this XDJ and my other one. 

Anyone happen to know what this gear is for? From my research is seems like older CDJ models like the CDJ-850 don't even have it. They only have a Gear A equivalent.