I think I have found a bug in ID CS6 / v8.0.
When I use the Gradient Feather effect at -180 degrees the preview of the effect doesn't show and instead I get to see a sharp edge where the effect should be.
The image below will make it more clear what I mean, the box in the middle doesn't show the effect correctly, the box below and above do show the effect correctly. It's just not showing at -180° exactly. Weird.
I just checked my collegues iMac and I can easily reproduce the problem on his system so I definately think it's a bug.
Anyone else seen this before?