Sony A7-A7r and Fuji X-T1 have a light leak issue (Both can be solved).
Sony A7r Light Leak video by Ferrell McCollough
The probably most popular mirrorless camera curiously share the same issue: A light leak on the mount!
As SonyAlphaRumors reports the issue is minor but visible. Sony is working on a fix for those that want to get rid of the problem. A cheap and temporary solution has been explained by Ferrel McCollough.
And also Camera.Reviewed reports about the Fuji X-T1 having the same issue. But Fuji already offers a service where you can send in the camera and they will repair it within 10 days!