I would suggest keeping your audio tracks outside of the nest, and only keep the video as multicam, that's how I would go about it.
Some of your tracks are mono, others are standard, your sequence is mono, and your audio files are stereo. To avoid the headache of figuring it out, just add three standard audio tracks and lay down your audio files there.
Hey Sami, Thank you for your quick answer! I did what you said and it worked out. I did modify though all audio tracks before I created the multicam nest so I don't understand why it happens, but anyways I got it now. Thanks.