Unless you've printed this with the intention of making the sides of the image lighter, it looks like you may want to check the light seals on your camera. If they're gummy, or flaking, you can replace them yourself with a light seal kit from Joh Goodman in Dallas (I found it on ebay), or another vendor. It takes some time, but it isn't difficult.
I too have noticed the severe halo on several of your prints and find it very distracting from a technical standpoint. I've been meaning to ask if it is intentional, or if it as a camera or darkroom problem?