Joe Carnahan, the director of Bunny Lake is the first official source to comment on Reese’s reasons for departure from the movie:

Scuttlebutt: How about NOTHING. How about a situation where the press tries to stir it up. These things happen. Movies go away every day. Reese is dealing with a lot of stuff in her life. So am I. We were running up against it as far as time for prep and shooting and scripting, etc. I had already commited to White Jazz and the longer we stretched Bunny the more in jeopardy the WJ schedule became. And there was just no way I could let that happen. I need a nice extended prep period for that flick.

And now I’ve got it.

That’s it guys. I wish there were some truly tasty bits of gossip but there just aren’t. Sorry.

Source: Smokin Joe Carnahan