diff --git a/pyproject.toml b/pyproject.toml
index 387236c5f..d23730b00 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ requires = [
     "cymem>=2.0.2,<2.1.0",
     "preshed>=3.0.2,<3.1.0",
     "murmurhash>=0.28.0,<1.1.0",
-    "thinc>=8.0.0a29,<8.0.0a40",
+    "thinc>=8.0.0a30,<8.0.0a40",
     "blis>=0.4.0,<0.5.0",
     "pytokenizations",
     "pathy"
diff --git a/requirements.txt b/requirements.txt
index eebe0852c..61d252ce4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,7 @@
 # Our libraries
 cymem>=2.0.2,<2.1.0
 preshed>=3.0.2,<3.1.0
-thinc>=8.0.0a29,<8.0.0a40
+thinc>=8.0.0a30,<8.0.0a40
 blis>=0.4.0,<0.5.0
 ml_datasets>=0.1.1
 murmurhash>=0.28.0,<1.1.0
diff --git a/setup.cfg b/setup.cfg
index 003015a6d..e6d02684e 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -34,13 +34,13 @@ setup_requires =
     cymem>=2.0.2,<2.1.0
     preshed>=3.0.2,<3.1.0
     murmurhash>=0.28.0,<1.1.0
-    thinc>=8.0.0a29,<8.0.0a40
+    thinc>=8.0.0a30,<8.0.0a40
 install_requires =
     # Our libraries
     murmurhash>=0.28.0,<1.1.0
     cymem>=2.0.2,<2.1.0
     preshed>=3.0.2,<3.1.0
-    thinc>=8.0.0a29,<8.0.0a40
+    thinc>=8.0.0a30,<8.0.0a40
     blis>=0.4.0,<0.5.0
     wasabi>=0.7.1,<1.1.0
     srsly>=2.1.0,<3.0.0
diff --git a/spacy/cli/init_config.py b/spacy/cli/init_config.py
index 776d520a5..723068106 100644
--- a/spacy/cli/init_config.py
+++ b/spacy/cli/init_config.py
@@ -70,7 +70,10 @@ def fill_config(
     msg = Printer(no_print=is_stdout)
     with show_validation_error(hint_fill=False):
         config = util.load_config(base_path)
-        nlp, _ = util.load_model_from_config(config, auto_fill=True)
+        nlp, _ = util.load_model_from_config(config, auto_fill=True, validate=False)
+    # Load a second time with validation to be extra sure that the produced
+    # config result is a valid config
+    nlp, _ = util.load_model_from_config(nlp.config)
     filled = nlp.config
     if pretraining:
         validate_config_for_pretrain(filled, msg)
diff --git a/spacy/tests/serialize/test_serialize_config.py b/spacy/tests/serialize/test_serialize_config.py
index 22dd4170d..9eae7c775 100644
--- a/spacy/tests/serialize/test_serialize_config.py
+++ b/spacy/tests/serialize/test_serialize_config.py
@@ -313,3 +313,13 @@ def test_config_optional_sections():
     # also how Config.interpolate works under the hood.
     new_config = Config().from_str(filled.to_str())
     assert new_config["pretraining"] == {}
+
+
+def test_config_auto_fill_extra_fields():
+    config = Config({"nlp": {"lang": "en"}, "training": {}})
+    assert load_model_from_config(config, auto_fill=True)
+    config = Config({"nlp": {"lang": "en"}, "training": {"extra": "hello"}})
+    nlp, _ = load_model_from_config(config, auto_fill=True, validate=False)
+    assert "extra" not in nlp.config["training"]
+    # Make sure the config generated is valid
+    load_model_from_config(nlp.config)