Steps to reproduce:
1. Open attached project "911008.zip"
2. Build "test" scene for UWP
3. Open VS solution
4. Build & Deploy on local machine
5. Place the cursor anywhere on the screen but the centre
6. Press left mouse button (without moving the mouse)
cursor gets locked and mouse movement rotates the camera while holding down the button

Expected result: Mouse X and Mouse Y axies return actual mouse input values (like in Editor)
Actual result: Mouse X and Mouse Y axies return invalid values in the first frame after locking cursor making cameras rotation to 'jump'

Not reproducible on Editor

Reproducible with: 5.5.3p3, 5.6.1p1, 2017.1.0b5