public bool KeepChildrenConnected { get; set; }

[SerializeField]
private AnimancerComponent _Animancer;

public void Initialize()
{
    _Animancer.Playable.KeepChildrenConnected = true;
}

Humanoid Rigs default this value to false so that playables will be disconnected from the graph while they are at 0 weight which stops it from evaluating them every frame.

Generic Rigs default this value to true because they do not always animate the same standard set of values so every connection change has a higher performance cost than with Humanoid Rigs which is generally more significant than the gains for having fewer playables connected at a time.

The default is set by Animancer.AnimancerPlayable.CreateOutput(UnityEngine.Animator,Animancer.IAnimancerComponent).