Noise Reduction in Audition CC2017

I'm working on reducing noise on a podcast that was recorded at a local bar. I have been able to reduce the noise my capturing a sound print on each of the separate tracks and applying the reduction to the whole track. For some reason though one of the tracks with the guest of the podcast has a lot of background noise coming through. Whats strange is when I have his track selected for editing by selecting the .wav file from the file box in upper left hand corner the background noise seems to be reduced. I only hear a lot of the background noise coming from his track when I select the multitrack with all four tracks on it. Im new to audition and any help regarding how this could be happening would be very helpful.