commit 103da92afc48ca2d2d2488b5b4391bcfd57887b5
Author: Tim Yale <yalet@lafayette.edu>
Date:   Fri Mar 21 15:34:52 2014 -0400

    LAF-2922: multiple service tickets cause 500 errors.

diff --git a/cas.module b/cas.module
index db3e013..f2e30a8 100644
--- a/cas.module
+++ b/cas.module
@@ -36,6 +36,12 @@ function cas_init() {
 
   // Process a single-sign out request.
   _cas_single_sign_out_check();
+  
+  // Protect against multiple ST problems.
+  if ($user->uid && isset($_GET['ticket'])) {
+    watchdog("debug", "here");
+    drupal_goto('');
+  }
 
   // If a user is not logged in, consider using CAS authentication.
   if (!$user->uid) {