One more item to tuck away in the Aperture corner of your mind...

Observed an odd behavior on Aperture 3.4.2 yesterday evening. After applying sharpening to a photo, I added a post-crop vignette. The vignette "altered" the sharpening in some areas of the photo. Quickly dealt with by brushing away the vignette from the impacted areas.

I don't quite know how better to describe this, so I captured what I experienced in a short video.