Adobe Audition Multitrack Mixdown Combines Takes

I'm an audiobook narrator and use multitrack (as it's non-destructive) in Audition with punch and roll. Every so often, Audition will export more than one "take" of the same text, leaving me with an exported file of overlapping narration. Which is, of course, unusable. 

Any thoughts on 1.) why it's doing this and 2.) how to make it stop?

Thank you!

- Craig