Reproduction steps:
1. Download project "ParentTest.zip" and open in Unity
2. Enter Play mode

Expected: object "Cube" rotates and all of its components stay enabled if enabled before
Actual: some of "Cube" object's components are disabled

Reproduced on: 5.5.4p4; 5.6.3p2; 2017.1.1f1; 2017.2.0b10; 2017.3.0a7

Note: "Cube" has a parent object when the parent object is deleted (OnDelete is triggered and "Cube" property parent is set to null), some of the components of the "Cube" are disabled;
Components which do not become disabled - Mesh, Physics, Miscellaneous (Billboard Renderer, Sprite Mask), Analytics.