Areaportal window issue

Certain area-portal windows in my map after fully fading out will show up as a closed area portal instead of what the func_areaportalwindow is suppose to show (a black brush.) I’ve done many little tests to see if I can solve it but so far I’ve got nothing.

Here is an example.

http://puu.sh/k7GMn/4a38d716bc.jpg

First image is just before fully faded, and the second is when it has exceeded the maximum distance.

I know it is not suppose to do this as another area-portal window doesn’t do it despite having the same settings.

Just to clarify, my compile log is clean of any errors.
Hope someone can help.

Did you place the areaportal brush in front of the black brush ?

Yes, but I have also done this elsewhere and it has worked fine.

[editline]11th September 2015[/editline]

Well, I just moved the portals behind the brush and it works…

Such a simple fix. Thanks

ideally they should be right on top of eachother, so it works properly from the other side as well.