Hey Peter, I have no way to thank you enough, my friend.
Phase correlation was my problem exactly. The tracks with this problem were indeed being left out of the mix. Well, it is quite strange that, after 8 years shooting weddings with wired audio, I only ended up with some phase problems just now. I mean, I handle all of my audios with several recorders (both Tascam and Zoom) and a multitude of digital audio-mixers available at the wedding and only after 200 of them I get this problem, hehehe!
I corrected it through Audition CC17, which offers a very simple and straight forward tool called phase analysis.
On this tool, you see the graphic and it shows exactly what the phase problem is (inverse, balance, and a third one I forgot about right now).
This forum is amazing and let’s keep on helping each other, guys!
See you soon.