Steps to reproduce:
1. Open the attached project (InputTestProject.zip)
2. Open the Assets/test.unity scene
3. Play the Scene
4. Double tap the upper left corner
5. Double tap the opposite corner
6. The Input.mousePosition is always one frame behind the state of the button being pressed

Expected result: Windows touch input events and positioning events should be synced
Actual result: Always one frame behind the state of the button being pressed

Note:
Tested with Surface 3

Reproduced with: 5.6.0p1, 2017.1.0b1
Not reproduced with: 5.5.3p1