Landscape Mode automatically turns on Game View in Viewport

Landscape Mode automatically turns on game view in the level Viewport.

Regression (yes) issue (does not) occur 4.13.2

1. Open Editor (any project)
2. Press dropdown menu in Viewport to ensure Game View is set to false
3. Switch to Landscape Mode
4. Check dropdown menu again

Results

Game Mode is set to True.

Expected

Game Mode is set to False.