diff --git a/connexion/validators/abstract.py b/connexion/validators/abstract.py
index bb6599eac..177a1f87d 100644
--- a/connexion/validators/abstract.py
+++ b/connexion/validators/abstract.py
@@ -76,7 +76,8 @@ def _insert_body(self, receive: Receive, *, body: t.Any, scope: Scope) -> Receiv
         bytes_body = json.dumps(body).encode(self._encoding)
 
         # Update the content-length header
-        new_scope = copy.deepcopy(scope)
+        new_scope = scope.copy()
+        new_scope["headers"] = copy.deepcopy(scope["headers"])
         headers = MutableHeaders(scope=new_scope)
         headers["content-length"] = str(len(bytes_body))