ProductFamilyModel : initProducts()

Model/Product/ProductFamilyModel.php

     public function __construct()
     {
         $this->productCategories = new ArrayCollection();
-        $this->products = new ArrayCollection();
         $this->qualityLabels = new ArrayCollection();
+        $this->initProducts();
+    }
+
+    public function initProducts()
+    {
+        $this->products = new ArrayCollection();
     }
 
     public function __toString()