At least this bug occurs in Unity 5.2.0p1 and 5.2.1f1, but not on 5.2.0f3.
Say X, Y are 2 game objects, where Y is parented to X. Generally when X rotates, Y will rotate correspondingly. I hope to prevent Y from being rotated and make it look at some point all the time, so I add to Y a script in which I implement the LateUpdate message to do the look-at thing. Since X only rotates in Update messages, so Y will ‘correct’ its rotation in the subsequent LateUpdate call.
This works well till 5.2.0p1. Does anyone else notice this? Is this a bug or something else?