When you have a Particle system parented to an object, and that Particle systems render mode is set to 'Mesh', and the Mesh applied in that slot is the parented object, the Particle Rotations will become wrong. If the Parent is rotated, the Child particle system won't rotate at all. If you personally rotate the Particle system transform, it does not mirror the shape of the Parent

To reproduce:

1. Download attached project "Case 518792 - Particle system hierarchy scaling produces incorrect final result - Fix Test.zip" and open in Unity
2. Open "rotationoverlife" scene
3. Enter Play mode
4. Rotate "Sphere" gameObject on Z axis to 45 degrees
5. Rotate "Particle System" gameObject on Z axis to 45 degrees

Expected results: The particle system would rotate with its parent and maintain the shape of a said parent when rotated separately
Actual results: The particle system does not rotate with a parent, and when rotated separately, it gets deformed and does not keep to the shape of the parent

Notes:
- This issue appears on both Windows and OSX
- A User said that on Unity 5.6.5 everything worked as expected

Reproduced on Unity 2017.4.12f1, 2018.1.9f2, 2018.2.11f1, 2018.3.0b4 and 2019.1.0a3