Moving multiple child objects, some of them move by their local axis. Having more than two child objects, only one of them moves by the global axis, other objects moves by their local axis. Setting parent objects Z axis rotation from 45 to 0 fixes the problem.

To reproduce:
1. Open users attached project "BugRepo.zip"
2. Open "repro.unity" scene
3. In the hierarchy expand "GameObject" and select Cube1 and Cube2 game objects
4. Drag them by Y and X axis

Expected result: objects move in the same direction
Actual result: Cube1 moves by his local axis

Reproduced on: 5.6.2p1 2017.1.0f1 2017.2.0b1
Not reproduced on: 5.6.2f1
Regression introduced on: 5.6.2p1