Too much light from the display is playing havoc with the 5D Mark III's AE sensor in some specific scenarios
There have been rumblings around the internet that Canon's new 5D Mark III DSLR has been having light leak issues here in its early stages.
Here's the description of the problem directly from the Canon advisory: "In extremely dark environments, if the LCD panel illuminates, the displayed exposure value may change as a result of the AE sensor’s detection of light from the LCD panel."
Canon is reportedly looking into a fix for the problem, but there isn't one quite yet. We'll post an update when we hear back, but until then, we're curious to hear whether or not you've experienced this problem.