Loose comparison causes the value not to be saved when the field is object (#42793)

Author: vsg24

src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php

@@ -1956,8 +1956,8 @@ public function originalIsEquivalent($key)
             return $this->fromDateTime($attribute) ===
                 $this->fromDateTime($original);
         } elseif ($this->hasCast($key, ['object', 'collection'])) {
-            return $this->castAttribute($key, $attribute) ==
-                $this->castAttribute($key, $original);
+            return $this->fromJson($attribute) ===
+                $this->fromJson($original);
         } elseif ($this->hasCast($key, ['real', 'float', 'double'])) {
             if (($attribute === null && $original !== null) || ($attribute !== null && $original === null)) {
                 return false;