It seems that this is a an issue with the LED's of the LCD backlight leaking light onto the metering sensor. The amount of light that's leaked is so small that in most situations it would effect exposure about 1/100th of a stop which is not noticeable to the human eye. The light doesn't leak onto the sensor so that's a non issue.
The far greater issue is when bright sunlight strikes the LCD and leaks to the metering sensor, that could noticeably affect exposure. (this is unconfirmed though)
I just tried this on my 5D II and 20D and this seems to be an issue there too. Clearly this is a small enough issue that it took 10 years to find, and everyone still took great photos, but if the LCD actually does leak light onto the metering sensor that should be fixed, otherwise, it's a non-issue.