Hearing all audio tracks even when Soloing one

Hi Guys,

I have encountered an issue when trying to edit a recording I have from vMix. I have multiple audio tracks, where the audio comes from different sources (different inputs within vMix), but despite this, I can still hear the other audio tracks when Soloing one track. Here's an image to help describe this

As you can see, I have multiple audio tracks here - A1 and A2 are the Master Audio (all tracks), A3 and A4 is just audio from one input (the presenter, in my case) and as you can see there are lengthy silent sections where he is not speaking, and the guest is speaking - as you can see on tracks A5 and A6. But when I try to listen to just the presenters' audio - I can still hear the guest's audio despite the audio track definitely showing no waveforms, so surely I shouldn't hear them?

I mention vMix as it is a recording in the vMix AVI format - I'm not sure if anyone has had similar problems with this format in the past before. I cant for the life of me figure out why I'm hearing noise when the track should be silent.

Any help would be greatly appreciated.

Many thanks,