I posted here about my 2.8F suffering from this, so thought I'd report back. After waiting several months involving sending the camera back to the shop where I bought it from and they claiming there was no light leak, followed by sending it to Harry Fleenor for a second opinion, Harry was able to find the source of this problem. It's indeed a light leak originating from a faulty seal around the taking lens (as originally hypothesized by Dan Daniel on this thread).
Some folks had suggested this was caused by an object in front of the taking lens (e.g. a strap). The attached photo (cropped to respect the subject of the photo's privacy) is what you get on an image when you get a strap in front of the taking lens - it blocks incoming light, so you see a dark band on the image, not a bright highlight.
Some folks had suggested this was caused by an object in front of the taking lens (e.g. a strap). The attached photo (cropped to respect the subject of the photo's privacy) is what you get on an image when you get a strap in front of the taking lens - it blocks incoming light, so you see a dark band on the image, not a bright highlight.