Steps to reproduce:

1. Open attached project
2. Open 'Main' scene
3. Click the pause button and then play the scene, the game will be paused at first frame
4. Notice that the two cubes created via script are randomly rotated while the instantiated cubes are positioned correctly

Note:
If the cubes are created in Update function, it can be observed, that for one frame they are positioned correctly (not rotated), but then the very next frame the rotation is messed up.

Reproduced with: 5.1.4f1, 5.3.0f3, 5.4.0a4
Not reproduced with: 5.0.4f1