How to reproduce:
1. Download attached project
2. Open the scene ParticleSortingFudgeTest.unity
3. Move “Particle System Right” (or left) along z axis

Actual result: “Particle System Right” (or left) rendered normally (red cover white) when z >= 0 but flip the order when z < 0.
Expected result: “Particle System Right” (or left) should render normally and same in the positive and negative z axis.

Reproduce with: 5.6.1f1, 5.6.3f1, 2017.1.0p3, 2017.2.0b5, 2017.3.0a1

Note: You can also change the transparencySortMode under “Main Camera”. Sorting fudge works fine under Orthgraphics & Perspective mode but breaks under CustomAxis mode.