失败保存状态 - 目标不在片段管理器中（setTargetFragment）

I've got a monkey crash whereby

我的猴子撞了

java.lang.IllegalStateException: Failure saving state: FragmentB has target not in fragment manager: FragmentA
at android.support.v4.app.FragmentManagerImpl.saveAllState(FragmentManager.java:1561)
at android.support.v4.app.FragmentActivity.onSaveInstanceState(FragmentActivity.java:475)
at com.acme.ParentActivity.onSaveInstanceState(Unknown Source)
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