Play() and Stop() affecting all particle system in object?

I have an object which has a particle system on it that is played by a script on the same object using the Play() and Stop() methods of the particle system. I access the particle system through a serialized ParticleSystem variable where I’ve dragged the particle system into the inspector. I have another particle system that is on a child object of this object. This particle system plays persistently and isn’t controlled or referenced by code.

However, when the Play() and Stop() are called on the first particle system they are also affecting the second particle system. I’ve verified this by commenting out all the code that affects the first particle system. Doing so allows the second particle system to persistently run like intended. As far as I understand it, this shouldn’t happen. I give the specific particle system to the script and it calls the methods on that particle system. Why should this affect a particle system on a child object?

There is a parameter on the play and stop functions to say whether children should be affected.