Since updating my BlackBerry Passport to version 10.3.1 last week, I have found that the display randomly flickers and/or a portion of the screen goes dark. This happens across different apps and menus. This same issue has been reported by a few other BlackBerry Passport users who have run the update.
I was in the middle of editing a calendar entry earlier today when the display began flickering and about half of the display eventually went black, leaving my editing messed up. I have experienced same while viewing photos.
Hopefully, BlackBerry will fix this bug quickly, as it is a big blow to usability.
NB: This bug seems to be a BlackBerry Passport issue only.