Saving + reopening Multitrack sessions in Audition issues

Hello everyone,
I do interviews for radio which I record on Audition. On the past couple of occasions, I’ve loaded the interview onto a multitrack, and then separated my voice and the interviewees onto different tracks. I then save the session.
However, when I reopen the session, I’ve discovered that my questions appear to have moved back to the interviewees track and what was my vocal track has random parts of the interviewee on it. This has happened twice now and I’ve wasted massive amounts of time having to re-edit what I thought I had done the day before.
Where am I going wrong?

The best way moving forward is to record on separate tracks.