Starting values such as color or start size become gradually ordered in the system when "Random Direction" is enabled.

Repro steps:
1. Open ParticleBug scene from attached project.
2. Select Particle System from Hierarchy.
3. In the inspector", enable "Random Direction" from the shape module of the particle.
4. Observe that the particle start color and start size are no longer random.

Expected outcome: random particle placement

Notes:
- Is regression, works in 5.3.1f1, broken in 5.4.0a2
- Occurs with Box, Sphere, and to a smaller degree wtih Hemisphere, which shows a mix of ordered and random placement.