Correctif

Solver/Product/ProductFamilySolver.php

             $products = $this->getProductsOnline($productFamily)->getValues();
             if (count($products) > 0) {
                 usort($products, $comparisonFunction);
-
                 return $products[0];
             }
         } else {
-            return $this->getOriginProduct($returnSelfIfNotActiveProducts);
+            return $this->getOriginProduct($productFamily);
         }
         if ($returnSelfIfNotActiveProducts) {
             return $productFamily;
     }
 
 
-    public function getOriginProduct(ProductFamilyInterface $productFamily): ProductInterface
+    public function getOriginProduct(ProductFamilyInterface $productFamily): ?ProductInterface
     {
         $products = $productFamily->getProducts();
 
                 return $product;
             }
         }
+
+        return null;
     }