diff --git a/lib/Doctrine/ODM/MongoDB/Proxy/Factory/StaticProxyFactory.php b/lib/Doctrine/ODM/MongoDB/Proxy/Factory/StaticProxyFactory.php
index 9d5e56938b..3dabf94ef0 100644
--- a/lib/Doctrine/ODM/MongoDB/Proxy/Factory/StaticProxyFactory.php
+++ b/lib/Doctrine/ODM/MongoDB/Proxy/Factory/StaticProxyFactory.php
@@ -14,9 +14,11 @@
 use Doctrine\Persistence\NotifyPropertyChanged;
 use ProxyManager\Factory\LazyLoadingGhostFactory;
 use ProxyManager\Proxy\GhostObjectInterface;
+use ReflectionClass;
 use ReflectionProperty;
 
 use function array_filter;
+use function array_merge;
 use function count;
 
 /**
@@ -130,6 +132,19 @@ private function createInitializer(
      * @return array<int, string>
      */
     private function skippedFieldsFqns(ClassMetadata $metadata): array
+    {
+        $skippedIdFieldsFqns        = $this->getIdFieldsFqns($metadata);
+        $skippedNonMappedFieldsFqns = $this->getUnmappedPropertyFqns($metadata);
+
+        return array_merge($skippedIdFieldsFqns, $skippedNonMappedFieldsFqns);
+    }
+
+    /**
+     * @param ClassMetadata<object> $metadata
+     *
+     * @return array<int, string>
+     */
+    private function getIdFieldsFqns(ClassMetadata $metadata): array
     {
         $idFieldFqcns = [];
 
@@ -140,6 +155,30 @@ private function skippedFieldsFqns(ClassMetadata $metadata): array
         return $idFieldFqcns;
     }
 
+    /**
+     * @param ClassMetadata<object> $metadata
+     *
+     * @return array<int, string>
+     */
+    private function getUnmappedPropertyFqns(ClassMetadata $metadata): array
+    {
+        $nonMappedFieldFqcns = [];
+
+        $reflectionClass = new ReflectionClass($metadata->getName());
+
+        foreach ($reflectionClass->getProperties() as $property) {
+            $propertyName = $property->getName();
+
+            if ($metadata->hasField($propertyName)) {
+                continue;
+            }
+
+            $nonMappedFieldFqcns[] = $this->propertyFqcn($property);
+        }
+
+        return $nonMappedFieldFqcns;
+    }
+
     private function propertyFqcn(ReflectionProperty $property): string
     {
         if ($property->isPrivate()) {