Logic Pro 9 Problem with Flex Time

Used Auto-Tune to edit a vocal.
Bounce Replaced the tuned vocal.
Turned on flex time -monophonic to edit the timing of the vocal performance
After the analyzing was finished, the region for the vocal is now twice the size and plays at half speed.

After reading your other post I think the problem is linked to your tempo change. A couple of ways to fix it. The most simple: option click the lower right corner and drag the region size back to one bar.