Fixed a bug in Route::withParam() method

CHANGELOG.md

@@ -4,6 +4,7 @@
 1. [](#bugfix)
     * Fixed error in `ImageMedium::url()` if the image cache folder does not exist
     * Fixed empty form flash name after update
+    * Fixed a bug in `Route::withParam()` method
 
 # v1.6.10
 ## 06/14/2019

system/src/Grav/Framework/Route/Route.php

@@ -313,9 +313,9 @@ class Route
      */
     protected function withParam($type, $param, $value)
     {
-        $oldValue = $this->{$type}[$param] ?? null;
+        $typeValue = $this->{$type}[$param] ?? null;
 
-        if ($oldValue === $value) {
+        if ($typeValue === $value) {
             return $this;
         }
 
@@ -323,7 +323,8 @@ class Route
         if ($value === null) {
             unset($new->{$type}[$param]);
         } else {
-            $new->{$type}[$param] = $value;
+            $typeValue[$param] = $value;
+            $new->{$type} = $typeValue;
         }
 
         return $new;