Why my ParticleSystem tree object loops correctly in edit mode, but only part of it in play mode?

Hi,

I'm facing a strange issue and have no clue about the reason it's happening.

I'm on Unity 5.3.2f1, and I'm creating a ground shockwave effect.

The parent object emits a series of Horizontal billboard waves, using an emission curve. It is set to loop, so it emits some waves and then stops for a while. Parented, I have 2 other particle systems to improve the effect. One emits a series of stretched rays from the center, while another spawns a circle of small billboarded particles. Both use a similar emission curve.

In Edit mode all works fine, all ParticleSystems loop perfectly, have the same duration and the "Loop" checkmark on.

The whole system is well above the floor.

When I press play, only the stretched rays loop. The others work one time only.

I created thousands of VFX before and never ran into this weird behaviour.

Could you please help me figure out what's happening?

Thanks for your time :)