diff --git a/src/app/units/states/tasks/tasks.coffee b/src/app/units/states/tasks/tasks.coffee
index eba3810469..518076516f 100644
--- a/src/app/units/states/tasks/tasks.coffee
+++ b/src/app/units/states/tasks/tasks.coffee
@@ -23,6 +23,22 @@ angular.module('doubtfire.units.states.tasks', [
   # Cleanup
   listeners = listenerService.listenTo($scope)
 
+  # Sets task key from URL parameters (safe for missing/empty values)
+  setTaskKeyFromUrlParams = (taskKeyString) ->
+    if taskKeyString?
+      # Ensure string format for safety
+      $scope.taskData.taskKey = newTaskService.taskKeyFromString("#{taskKeyString}")
+    else
+      $scope.taskData.taskKey = null
+
+  # Sets URL parameters for the task key (avoid redundant state.go)
+  setTaskKeyAsUrlParams = (task) ->
+    newKey = task?.taskKeyToUrlString()
+    # If key hasn't changed, do nothing
+    return if $state.params.taskKey == newKey
+    # Change URL of new task without notify
+    $state.go($state.$current, {taskKey: newKey}, {notify: false})
+
   # Task data wraps:
   #  * the URL task composite key (project username + task def abbreviation) sourced from the URL,
   #  * the task source used for the task inbox list,
@@ -33,35 +49,21 @@ angular.module('doubtfire.units.states.tasks', [
     source: null
     selectedTask: null
     onSelectedTaskChange: (task) ->
-      taskKey = task?.taskKey()
-      $scope.taskData.taskKey = taskKey
+      $scope.taskData.taskKey = task?.taskKey() ? null
       setTaskKeyAsUrlParams(task)
   }
 
-  # Sets URL parameters for the task key
-  setTaskKeyAsUrlParams = (task) ->
-    # Change URL of new task without notify
-    $state.go($state.$current, {taskKey: task?.taskKeyToUrlString()}, {notify: false})
-
-  # Sets task key from URL parameters
-  setTaskKeyFromUrlParams = (taskKeyString) ->
-    # Propagate selected task change downward to search for actual task
-    # inside the task inbox list
-    $scope.taskData.taskKey = newTaskService.taskKeyFromString(taskKeyString)
-
-  # Child states will use taskKey to notify what task has been
-  # selected by the child on first load.
+  # Child states will use taskKey to notify what task has been selected on first load.
   taskKey = $transition$.params().taskKey
   setTaskKeyFromUrlParams(taskKey)
 
-  # Whenever the state is changed, we look at the taskKey in the URL params
-  # see if we can set it as an actual taskKey object
+  # Whenever the state is changed, update taskKey from URL params.
   listeners.push $scope.$on '$stateChangeStart', ($event, toState, toParams, fromState, fromParams) ->
     setTaskKeyFromUrlParams(toParams.taskKey)
-    # Use preventDefault to prevent destroying the child state's
-    # scope if they are the same states. Otherwise, if they are
-    # the same, we destroy the state's scope and recreate it again
-    # unnecessarily; doing so will cause a re-request in the task
-    # list which is not required.
-    $event.preventDefault() if fromState == toState && fromParams.unitId == toParams.unitId
+
+    # Prevent unnecessary scope teardown/rebuild only when nothing actually changes.
+    sameState = fromState == toState
+    sameUnit  = fromParams.unitId == toParams.unitId
+    sameTask  = fromParams.taskKey == toParams.taskKey
+    $event.preventDefault() if sameState && sameUnit && sameTask
 )