I thought I was going crazy because I'm always in continuous AF these days and the exposure in the EVF was not right (compared to the actual photo taken). I'm glad this was a bug and fixed. Go get your update :)
The firmware bug has been fixed, which caused that the brightness of the preview image in the EVF was changing dramatically depending on the brightness of the subject while half pushing the shutter button by setting “FOCUS MODE” to “CONTINUOUS AF”.