Update bioimageio/spec/_internal/common_nodes.py

Co-authored-by: Copilot <[email protected]>

Author: FynnBe

bioimageio/spec/_internal/common_nodes.py

@@ -260,7 +260,7 @@ def extract_flat_keys(d: Dict[Any, Any], key: str = "") -> Iterable[str]:
                 if is_dict(v):
                     yield from extract_flat_keys(v, key=f"{key}.{k}" if key else k)
 
-                yield k
+                yield f"{key}.{k}" if key else k
 
         given_keys = set(extract_flat_keys(given))
         full_keys = set(extract_flat_keys(full))