Problems taking screenshots using anti-aliasing

Hi folks.

Been Googling for hours and can't find a solution to a problem I've been having with anti-aliasing and taking screenshots.

My script runs through all the cameras in the level and takes a screenshot of them. Everything works nicely and quickly, exporting out 60+ 2048x1280 pics in no time at all. Sounds good.

Here's where it falls down. After enabling anti-aliasing about 75% of the renders will work (and look great and anti-aliased!) but about 25% will fail and save another camera's view as the texture! The cameras that fail fail consistently, but I can't see anything different about those cameras than the ones that work.

Here's my script:

 using UnityEngine;
 using System.Collections;
 
 public class TakeScreenshotMaster : MonoBehaviour {
 
 
 
     public int resWidth         = 2048; 
     public int resHeight         = 1280;
     public string cameraName     = "";
     
     private bool takeHiResShot = false;
     
     public static string ScreenShotName(int width, int height, string cameraName) {
 
         Debug.Log(string.Format("ScreenShotName: Name is now: {0}", cameraName));
 
         return string.Format("d:/screenshots/{4}_{1}x{2}_{3}.png", 
                              Application.dataPath, 
                              width, height, 
                              System.DateTime.Now.ToString("yyyy-MM-dd_HH-mm-ss"),
                              cameraName);
 
     }
     
     // Last to run...
     void LateUpdate() {
 
         takeHiResShot |= Input.GetKeyDown("k");
 
         if (takeHiResShot) 
         {
             Debug.Log(string.Format("k press detected!"));
             takeHiResShot = false;
             StartCoroutine(TakeScreenshotsOfEverything());
         }
     }
 
 
     IEnumerator TakeScreenshotsOfEverything()
     {
 
         Debug.Log(string.Format("Printing all screens!"));
 
         // Create new game object to hold all possible cameras...
         GameObject[] cameras = GameObject.FindGameObjectsWithTag("Camera");
         
         // Loop through each tagged camera...
         foreach (GameObject cams in cameras){
 
             // Get next camera...
             Camera theCam = cams.GetComponent<Camera>() as Camera;
             theCam.enabled = true;
 
             yield return new WaitForEndOfFrame();
             
             RenderTexture rt = new RenderTexture(resWidth, resHeight, 24);
         
             rt.antiAliasing = 1;
             rt.filterMode = FilterMode.Trilinear;
 
             theCam.targetTexture = rt;
             
             Texture2D screenShot = new Texture2D(resWidth, resHeight, TextureFormat.RGB24, false);
             
             RenderTexture.active = rt;
             theCam.Render();
 
             screenShot.ReadPixels(new Rect(0, 0, resWidth, resHeight), 0, 0);
             
             // Cleanup...
             theCam.targetTexture = null;
             RenderTexture.active = null; // JC: added to avoid errors
             Destroy(rt);
             theCam.enabled = false;
 
             // Write to file...
             byte[] bytes = screenShot.EncodeToPNG();
             string filename = ScreenShotName(resWidth, resHeight, theCam.name);
             System.IO.File.WriteAllBytes(filename, bytes);
             
             Debug.Log("Capture!");
         }  
 
 
     }
 
 
     // Use this for initialization
     void Start () {
         Debug.Log("Master camera reporting for duty!");
 
         // Create new game object to hold all possible cameras...
         GameObject[] cameras = GameObject.FindGameObjectsWithTag("Camera");
 
         // Loop through each tagged camera...
         // Disable each for now...
         foreach (GameObject cams in cameras){
             Camera theCam = cams.GetComponent<Camera>() as Camera;
             theCam.enabled = false;
         }  
 
         // Enable the first camera...
         //Camera firstCamera = cameras [0].GetComponent<Camera> () as Camera;
         //firstCamera.enabled = true;
     }
 
 
 
     // Update is called once per frame
     void Update () {
         //Debug.Log(string.Format("Update: Camera {0} is running!", cameraName));
         //camera.
     }
 
 }
 

Pulling my hair out with this one! Does anyone have any ideas? Like I said, it works 100% if I don't use anti-aliasing, and 75% will work if I enable anti-aliasing, with 25% fail by rendering one of the other working cameras instead.

Cheers, Chris