iOS flickers to portrait mode when phone locked then opened again

iOS flickers to portrait mode when phone is locked then opened again.

1. Open Editor (any project)
2. In Project Settings>iOS>Orientation and set the phone to only accept landscape left and right orientation (see attached image)
3. Launch to iOS device
4. Once device picks up the project, check to ensure it is in landscape left or right mode
5. Press the power button to lock the phone
6. Press the power button again to unlock the phone
7. Press the home button to re-open the phone to the project

Results

After a brief pause, the phone quickly rotates to portrait mode before resetting to landscape mode.

Expected

Phone does not rotate to portrait mode.