Steps to reproduce:

1. Download and import attached project. (AutoSimulate.zip)
2. Open scene: main.
3. Select Green particle system.
4. Disable and Enable it again in the inspector.

Expected result. After enabling, green particle system reappears and simulates.
Actual result: Particle system does not simulate automatically after enabling it.

Workaround: You need to stop and start simulation or select it in hierarchy again.

Reproduced on: 5.4.0b5, 5.3.2p2, 5.2.4f1