When returning from fullscreen mode, the view is redrawn as the resolution of windowed mode, but the camera's view only draws: what was the bottom left corner was when in fullscreen (quadrant 3).
Result: windowed view is drawn as quadrant 3 of the fullscreen view
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-44419 in the post.
| 0 | 
| Component | UE - Platform - Mobile | 
|---|---|
| Affects Versions | 4.16.1, 4.17 | 
| Target Fix | 4.17 | 
| Fix Commit | 3462166 | 
|---|---|
| Main Commit | 3496903 | 
| Created | Apr 26, 2017 | 
|---|---|
| Resolved | May 26, 2017 | 
| Updated | Sep 23, 2019 |