diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 5620d0ac5e..6471fb80b9 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -1,10 +1,10 @@
 Yii Framework 2 Change Log
 ==========================
 
-2.0.12 under development
+2.0.11.2 under development
 --------------------------
 
-- no changes in this release.
+- Bug #13508: Fixed duplicate attachment of behavior BC break (cebe)
 
 
 2.0.11.1 February 02, 2017
diff --git a/framework/base/Component.php b/framework/base/Component.php
index 4c73e9fab3..21880846fc 100644
--- a/framework/base/Component.php
+++ b/framework/base/Component.php
@@ -669,14 +669,14 @@ class Component extends Object
         if (is_int($name)) {
             $behavior->attach($this);
             $this->_behaviors[] = $behavior;
+        } else {
+            if (isset($this->_behaviors[$name])) {
+                $this->_behaviors[$name]->detach();
+            }
+            $behavior->attach($this);
+            $this->_behaviors[$name] = $behavior;
         }
 
-        if (isset($this->_behaviors[$name])) {
-            $this->_behaviors[$name]->detach();
-        }
-        $behavior->attach($this);
-        $this->_behaviors[$name] = $behavior;
-
         return $behavior;
     }
 }
diff --git a/tests/framework/base/BehaviorTest.php b/tests/framework/base/BehaviorTest.php
index 9a950f6990..c5ec181b13 100644
--- a/tests/framework/base/BehaviorTest.php
+++ b/tests/framework/base/BehaviorTest.php
@@ -22,6 +22,9 @@ class FooClass extends Component
 
 class BarBehavior extends Behavior
 {
+    public static $attachCount = 0;
+    public static $detachCount = 0;
+
     public $behaviorProperty = 'behavior property';
 
     public function behaviorMethod()
@@ -46,6 +49,18 @@ class BarBehavior extends Behavior
 
         return parent::hasMethod($name);
     }
+
+    public function attach($owner)
+    {
+        self::$attachCount++;
+        parent::attach($owner);
+    }
+
+    public function detach()
+    {
+        self::$detachCount++;
+        parent::detach();
+    }
 }
 
 /**
@@ -59,11 +74,16 @@ class BehaviorTest extends TestCase
         $this->mockApplication();
     }
 
-    public function testAttachAndAccessing()
+    public function testAttachAndAccessingWithName()
     {
+        BarBehavior::$attachCount = 0;
+        BarBehavior::$detachCount = 0;
+
         $bar = new BarClass();
         $behavior = new BarBehavior();
         $bar->attachBehavior('bar', $behavior);
+        $this->assertEquals(1, BarBehavior::$attachCount);
+        $this->assertEquals(0, BarBehavior::$detachCount);
         $this->assertEquals('behavior property', $bar->behaviorProperty);
         $this->assertEquals('behavior method', $bar->behaviorMethod());
         $this->assertEquals('behavior property', $bar->getBehavior('bar')->behaviorProperty);
@@ -71,14 +91,37 @@ class BehaviorTest extends TestCase
 
         $behavior = new BarBehavior(['behaviorProperty' => 'reattached']);
         $bar->attachBehavior('bar', $behavior);
+        $this->assertEquals(2, BarBehavior::$attachCount);
+        $this->assertEquals(1, BarBehavior::$detachCount);
         $this->assertEquals('reattached', $bar->behaviorProperty);
     }
 
+    public function testAttachAndAccessingAnonymous()
+    {
+        BarBehavior::$attachCount = 0;
+        BarBehavior::$detachCount = 0;
+
+        $bar = new BarClass();
+        $behavior = new BarBehavior();
+        $bar->attachBehaviors([$behavior]);
+        $this->assertEquals(1, BarBehavior::$attachCount);
+        $this->assertEquals(0, BarBehavior::$detachCount);
+        $this->assertEquals('behavior property', $bar->behaviorProperty);
+        $this->assertEquals('behavior method', $bar->behaviorMethod());
+    }
+
     public function testAutomaticAttach()
     {
+        BarBehavior::$attachCount = 0;
+        BarBehavior::$detachCount = 0;
+
         $foo = new FooClass();
+        $this->assertEquals(0, BarBehavior::$attachCount);
+        $this->assertEquals(0, BarBehavior::$detachCount);
         $this->assertEquals('behavior property', $foo->behaviorProperty);
         $this->assertEquals('behavior method', $foo->behaviorMethod());
+        $this->assertEquals(1, BarBehavior::$attachCount);
+        $this->assertEquals(0, BarBehavior::$detachCount);
     }
 
     public function testMagicMethods()