Can't access animation after combining meshes.

I'm using a script attached to the parent of an .fbx model to add a script to each child that tells me when they've been clicked. It also combines all the meshes of the children and makes a mesh filter and renderer at the top of the hierarchy, which lets me change the shader on the object when any part of it is clicked. I want to be able to step through the animation using a slider, and I have that working as well. The problem is that they don't work together. I'm not sure why I can't access `animation["Take 001"].time` if I combine the meshes.

Here's the code:

 #pragma downcast
 #pragma strict
 
 @script RequireComponent(MeshFilter)
 @script RequireComponent(MeshRenderer)

 var HighlightColor : Color = Color.red;
 var startSliderValue : float = 0.0;
 var endSliderValue : float = 1.0; 
 var followStart = true;
 var followEnd = false;
 var selected = false;
 private var shaderNormal : Shader; 
 private var shaderHighlighted : Shader;

 function Start() {
   animation["Take 001"].weight = 1; 
   animation["Take 001"].enabled = true;    
   animation["Take 001"].speed = 0; 
   animation["Take 001"].wrapMode = WrapMode.PingPong;
 
   for (var child : Transform in transform) {
     child.position += transform.position;
     addRecursively(child, "ChildClicked");
   }
   transform.position = Vector3.zero;
   transform.rotation = Quaternion.identity;    
   var meshFilters = GetComponentsInChildren.<MeshFilter>();
   var combine : CombineInstance[] = new CombineInstance[meshFilters.Length-1];
   var index = 0;
   for (var i = 0; i < meshFilters.Length; i++) {
     if (meshFilters[i].sharedMesh == null) continue;
       combine[index].mesh = meshFilters[i].sharedMesh;
       combine[index++].transform = meshFilters[i].transform.localToWorldMatrix;
       meshFilters[i].renderer.enabled = false;
   }
   GetComponent(MeshFilter).mesh = new Mesh();
   GetComponent(MeshFilter).mesh.CombineMeshes(combine);
   renderer.material = meshFilters[1].renderer.sharedMaterial;
 }
 
 function addRecursively(parent : Transform, script : String) {
   for (var child : Transform in parent) {
     addRecursively(child, script);
   }
   var scriptExists : Component = parent.GetComponent(script);
   if (!scriptExists) {
     parent.gameObject.AddComponent(script);
   }
 }
 
 function Update() { 
   if (followStart == true) {  
     animation["Take 001"].time = startSliderValue;
     followEnd = false;
   }  
   else {
     followEnd = true;
   }
   if (followEnd == false) { 
     followStart = true; 
   }
   else {
     animation["Take 001"].time = endSliderValue;  
     followStart = false;
   }
 }
 
 function Clicked() { 
   selected = !selected;
   if(renderer.material.shader == shaderNormal) { 
     renderer.material.shader = shaderHighlighted; 
     renderer.material.SetColor("_OutlineColor", HighlightColor);
   }
   else { 
     renderer.material.shader = shaderNormal;
   } 
 }