After holding any mouse button down and pressing escape to quit the game, using the right mouse button to move in the viewport locks it to the left and right bounds of the viewport. Sometimes moving this way will not move the camera at all or jump it around.
1. Create new empty project.
2. Enable use mouse for touch events through Edit>Project Settings
3. Click play in editor
4. While holding any mouse button (in game), press escape to quit game.
5. Right-click to try to rotate in the viewport.
Results: After holding any mouse button down and pressing escape to quit the game, using the right mouse button to move in the viewport lock it to the left and right bounds of the viewport. Sometimes moving this way will not move the camera at all or jump it around.
Expected: Drag functions smoothly moves throughout the event graph.
How to fix (until it happens next time):
1. Play in editor
2. Click mouse in game view
3. Quit game or restart the editor.
Head over to the existing Questions & Answers thread and let us know what's up.