mem4k

I noticed something similar happening on mine. The eyecup was slightly unseated. All it took it was a very slight twist for it reseat and the EVF switching back and forth with the LCD was working correctly again. I'm assuming that the problem was eyecup interfering with sensor that decides where to show the display. The other option is to try is to use the EVF view button to switch to LCD display only. That worked even when the eyecup was unseated.