Are you using VS5? or still on 4.2.5? In VS5 if you open up the developer console with TAB it will show you the way border for your scene as well as the developer console. It also shows you the destination of character when you click somewhere inside of the way border, but if you click outside of way border it shows you the calculated path instead - maybe you could use that to get a better understanding of what your scene is doing.
You can see the calculation being made in the red thing - I clicked outside of the way border. If you click inside it just creates a little square but doesn't show calculated path line thing.
P.S: if you aren't using VS5 & do decide to install it & have a go, then don't forget to create a duplicate copy of your actual ved & use the copy instead as you'll no longer be able to use the ved you open/save in VS5 for VS4 again. So, yeah... always
make sure you create backup copies!