After seeing Marla, the narrator meets Bob again. Bob still greets him as Cornelius and says "we all thought you were dead", referring to the support groups he used to go to, so it is clear that Bob has not seen the narrator since the support groups. Then Bob reveals that he goes to fight clubs on Tuesdays and Thursdays. The narrator says he goes on Saturdays.
Upon first seeing the film this makes sense. Presumably Tyler runs the club alone on Tuesdays and Thursdays while the narrator either runs the club or just goes along with Tyler on Saturdays. However, given the plot twist, how could Bob go to fight club and not recognize the narrator?
I've thought that perhaps the narrator (either as himself or as Tyler) might have not run the club on Tuesdays and Thursdays but that doesn't really seem to make sense given the whole feel of the club with the ritualistic rule-giving which I doubt would be given by anyone except the leader as well as later on when the narrator talks about how he owned fight club as much as Tyler did in the scene before the car crash.
I've also considered that perhaps he dressed differently when he was acting as Tyler alone but even in his flashbacks when he realizes that he and Tyler are the same person, he never appears as Tyler to others. He always appears looking like himself in Tyler's position.
Am I incorrectly dismissing one of these explanations or have I missed something?