sorry for not being clearer...
To adjust fades on an audio region open the inspector:
Expose the region parameter box if it's not already displaying by clicking on the disclosure arrow.
(please see page 42 in the Logic Pro 8 user manual).
Now, make sure the region before the unwanted audio begins playing is selected. The region parameter box will now update to show the parameters specific to the selected region in the Arrange.
If you have an audio region selected the region parameters box will look something like this:
I found that the fade out was the problem. You'll notice that next to the fade out value are the (actually pointing upwards and downwards in logic). If you click on that symbol a drop down menu appears allowing you to select a different fade type. If you have any type of fade other than 'Out' selected this could be the problem.
Select 'Out' and see if the problem persists. If it doesn't this is because the other type of fades ( X, EqP, XS) can only be applied to consecutive regions. So Logic seems to be remembering an audio region that once used to be crossfaded with the existing region.
For more info check out page 345 of the Logic Pro 8 User Manual which explains in more depth the type of fades.
If the above doesn't help or work for you try deleting the fade files:
Options > Audio > Delete Fade Files
By the way, an overview is basically the graphic file that Logic uses/creates to display the waveform of an audio file.
Let us know if you do/don't have (any) success!