If the game object was first parented to a Canvas and then the Canvas component was added to it, the overrideSorting property cannot be set. However, if the Canvas component was added to the object before parenting it to another Canvas, overrideSorting property will be set properly.

To reproduce:

1. Open the project, attached by the tester (overrideSortingBug.zip)
2. Open the "scene" scene
3. Enter Play mode
4. Observe the "new Canvas" game object's Canvas component, overrideSorting will be false (should be true)

Expected: overrideSorting property is set properly with any order of operations

Reproduced in 5.6.0f1, 5.6.0f3
Did not reproduce in 5.5.4f1, 5.6.0b11, 5.6.1f1, 5.6.2p2, 2017.1.0f2, 2017.2.0b2
Regression introduced in 5.6.0f1

Fixed in 5.6.1f1