diff --git a/spacy/language.py b/spacy/language.py
index 0606a57ab..68dbd2c75 100644
--- a/spacy/language.py
+++ b/spacy/language.py
@@ -1726,6 +1726,8 @@ class Language:
             ).merge(config)
         if "nlp" not in config:
             raise ValueError(Errors.E985.format(config=config))
+        # auto-fill [nlp]
+        config["nlp"] = Config(cls.default_config["nlp"]).merge(config["nlp"])
         config_lang = config["nlp"].get("lang")
         if config_lang is not None and config_lang != cls.lang:
             raise ValueError(
@@ -2101,13 +2103,6 @@ class Language:
         DOCS: https://spacy.io/api/language#from_disk
         """
 
-        def deserialize_config(path: Path) -> None:
-            if path.exists():
-                config = Config().from_disk(
-                    path, interpolate=False, overrides=overrides
-                )
-                self.config.merge(config)
-
         def deserialize_meta(path: Path) -> None:
             if path.exists():
                 data = srsly.read_json(path)
@@ -2122,7 +2117,10 @@ class Language:
 
         path = util.ensure_path(path)
         deserializers = {}
-        deserializers["config.cfg"] = deserialize_config
+        if Path(path / "config.cfg").exists():
+            deserializers["config.cfg"] = lambda p: self.config.from_disk(
+                p, interpolate=False, overrides=overrides
+            )
         deserializers["meta.json"] = deserialize_meta
         deserializers["vocab"] = deserialize_vocab
         deserializers["tokenizer"] = lambda p: self.tokenizer.from_disk(  # type: ignore[union-attr]
@@ -2177,10 +2175,6 @@ class Language:
         DOCS: https://spacy.io/api/language#from_bytes
         """
 
-        def deserialize_config(b):
-            config = Config().from_bytes(b, interpolate=False)
-            self.config.merge(config)
-
         def deserialize_meta(b):
             data = srsly.json_loads(b)
             self.meta.update(data)
@@ -2189,7 +2183,9 @@ class Language:
             self.vocab.vectors.name = data.get("vectors", {}).get("name")
 
         deserializers: Dict[str, Callable[[bytes], Any]] = {}
-        deserializers["config.cfg"] = deserialize_config
+        deserializers["config.cfg"] = lambda b: self.config.from_bytes(
+            b, interpolate=False
+        )
         deserializers["meta.json"] = deserialize_meta
         deserializers["vocab"] = lambda b: self.vocab.from_bytes(b, exclude=exclude)
         deserializers["tokenizer"] = lambda b: self.tokenizer.from_bytes(  # type: ignore[union-attr]
diff --git a/spacy/tests/serialize/test_serialize_config.py b/spacy/tests/serialize/test_serialize_config.py
index 85e6f8b2c..65a30e165 100644
--- a/spacy/tests/serialize/test_serialize_config.py
+++ b/spacy/tests/serialize/test_serialize_config.py
@@ -205,8 +205,7 @@ def test_issue8190():
 
 def test_create_nlp_from_config():
     config = Config().from_str(nlp_config_string)
-    with pytest.raises(ConfigValidationError):
-        load_model_from_config(config, auto_fill=False)
+    assert "initialize" not in config
     nlp = load_model_from_config(config, auto_fill=True)
     assert nlp.config["training"]["batcher"]["size"] == 666
     assert len(nlp.config["training"]) > 1
diff --git a/spacy/util.py b/spacy/util.py
index d0e2fb83f..8cc89217d 100644
--- a/spacy/util.py
+++ b/spacy/util.py
@@ -532,7 +532,7 @@ def load_model_from_config(
     disable: Union[str, Iterable[str]] = _DEFAULT_EMPTY_PIPES,
     enable: Union[str, Iterable[str]] = _DEFAULT_EMPTY_PIPES,
     exclude: Union[str, Iterable[str]] = _DEFAULT_EMPTY_PIPES,
-    auto_fill: bool = True,
+    auto_fill: bool = False,
     validate: bool = True,
 ) -> "Language":
     """Create an nlp object from a config. Expects the full config file including