NullReferenceException in RootPropModNodeContainer.Add

[anatawa12]

System.NullReferenceException: Object reference not set to an instance of an object
  at Anatawa12.AvatarOptimizer.AnimatorParsersV2.RootPropModNodeContainer.Add (Anatawa12.AvatarOptimizer.AnimatorParsersV2.ComponentNodeContainer container, System.Boolean alwaysApplied) [0x00000] in .\Packages\com.anatawa12.avatar-optimizer\Editor\AnimatorParserV2\NodeContainer.cs:44 
  at Anatawa12.AvatarOptimizer.AnimatorParsersV2.AnimatorParser.CollectAvatarRootAnimatorModifications (nadena.dev.ndmf.BuildContext session, Anatawa12.AvatarOptimizer.AnimatorParsersV2.RootPropModNodeContainer modifications) [0x00014] in .\Packages\com.anatawa12.avatar-optimizer\Editor\AnimatorParserV2\AnimatorParser.cs:171 
  at Anatawa12.AvatarOptimizer.AnimatorParsersV2.AnimatorParser.GatherAnimationModifications (nadena.dev.ndmf.BuildContext context) [0x00006] in .\Packages\com.anatawa12.avatar-optimizer\Editor\AnimatorParserV2\AnimatorParser.cs:32 
  at Anatawa12.AvatarOptimizer.Processors.ParseAnimator.Execute (nadena.dev.ndmf.BuildContext context) [0x00014] in .\Packages\com.anatawa12.avatar-optimizer\Editor\Processors\ParseAnimator.cs:17 
  at nadena.dev.ndmf.Pass`1[T].nadena.dev.ndmf.IPass.Execute (nadena.dev.ndmf.BuildContext context) [0x00000] in .\Packages\nadena.dev.ndmf\Editor\API\Fluent\Pass.cs:64 
  at nadena.dev.ndmf.ConcretePass.Execute (nadena.dev.ndmf.BuildContext context) [0x00000] in .\Packages\nadena.dev.ndmf\Editor\API\Solver\PluginResolver.cs:36 
  at nadena.dev.ndmf.BuildContext.RunPass (nadena.dev.ndmf.ConcretePass pass) [0x00124] in .\Packages\nadena.dev.ndmf\Editor\API\BuildContext.cs:350 
  at Anatawa12.AvatarOptimizer.AnimatorParsersV2.RootPropModNodeContainer.Add (Anatawa12.AvatarOptimizer.AnimatorParsersV2.ComponentNodeContainer container, System.Boolean alwaysApplied) [0x00000] in .\Packages\com.anatawa12.avatar-optimizer\Editor\AnimatorParserV2\NodeContainer.cs:44 
  at Anatawa12.AvatarOptimizer.AnimatorParsersV2.AnimatorParser.CollectAvatarRootAnimatorModifications (nadena.dev.ndmf.BuildContext session, Anatawa12.AvatarOptimizer.AnimatorParsersV2.RootPropModNodeContainer modifications) [0x00014] in .\Packages\com.anatawa12.avatar-optimizer\Editor\AnimatorParserV2\AnimatorParser.cs:171 
  at Anatawa12.AvatarOptimizer.AnimatorParsersV2.AnimatorParser.GatherAnimationModifications (nadena.dev.ndmf.BuildContext context) [0x00006] in .\Packages\com.anatawa12.avatar-optimizer\Editor\AnimatorParserV2\AnimatorParser.cs:32 
  at Anatawa12.AvatarOptimizer.Processors.ParseAnimator.Execute (nadena.dev.ndmf.BuildContext context) [0x00014] in .\Packages\com.anatawa12.avatar-optimizer\Editor\Processors\ParseAnimator.cs:17 
  at nadena.dev.ndmf.Pass`1[T].nadena.dev.ndmf.IPass.Execute (nadena.dev.ndmf.BuildContext context) [0x00000] in .\Packages\nadena.dev.ndmf\Editor\API\Fluent\Pass.cs:64 
  at nadena.dev.ndmf.ConcretePass.Execute (nadena.dev.ndmf.BuildContext context) [0x00000] in .\Packages\nadena.dev.ndmf\Editor\API\Solver\PluginResolver.cs:36 
  at nadena.dev.ndmf.BuildContext.RunPass (nadena.dev.ndmf.ConcretePass pass) [0x00124] in .\Packages\nadena.dev.ndmf\Editor\API\BuildContext.cs:350