diff --git a/graphify/build.py b/graphify/build.py
index bdd56a31..a3ef6f30 100644
--- a/graphify/build.py
+++ b/graphify/build.py
@@ -201,15 +201,20 @@ def graph_has_legacy_ids(nodes: list, root: str | Path | None = None, sample: in
     stem) rather than the full repo-relative path. Read-only consumers (query,
     serve) use this to nudge the user to rebuild, since they don't re-extract.
 
-    Heuristic and cheap: samples nodes with a relative ``source_file`` and returns
-    True as soon as one ID matches an OLD stem form but NOT the canonical full-path
-    form. Absolute/sourceless nodes are skipped (can't be classified)."""
+    Heuristic and cheap: only **file-level** nodes (source_location ``L1``) are
+    inspected, because their ID is unambiguously the file stem. Symbol nodes are
+    skipped — some extractors scope a symbol by package/directory (Go's
+    ``_make_id(pkg_dir, name)`` → ``sub_thing``), which can coincide with an old
+    file-stem form and would otherwise false-positive. Returns True as soon as one
+    file node's ID matches an OLD stem form but not the canonical full-path form."""
     from graphify.extractors.base import _file_stem
     _r = str(root) if root is not None else None
     checked = 0
     for node in nodes:
         if not isinstance(node, dict):
             continue
+        if str(node.get("source_location") or "") != "L1":
+            continue  # only file-level nodes carry an unambiguous file-stem ID
         nid = node.get("id")
         sf = node.get("source_file")
         if not nid or not isinstance(nid, str) or not sf:
diff --git a/tests/test_build.py b/tests/test_build.py
index 8a5d9dc9..2d8bfdd6 100644
--- a/tests/test_build.py
+++ b/tests/test_build.py
@@ -726,13 +726,18 @@ def test_graph_has_legacy_ids_detects_old_scheme():
     """The read-only-consumer nudge (query/serve) flags a pre-#1504 graph and
     leaves a canonical one alone."""
     from graphify.build import graph_has_legacy_ids
-    old = [{"id": "api_readme", "source_file": "docs/v1/api/README.md", "type": "document"}]
-    new = [{"id": "docs_v1_api_readme", "source_file": "docs/v1/api/README.md", "type": "document"}]
+    old = [{"id": "api_readme", "source_file": "docs/v1/api/README.md", "type": "document", "source_location": "L1"}]
+    new = [{"id": "docs_v1_api_readme", "source_file": "docs/v1/api/README.md", "type": "document", "source_location": "L1"}]
     assert graph_has_legacy_ids(old, root=".") is True
     assert graph_has_legacy_ids(new, root=".") is False
-    # sourceless / top-level nodes don't false-positive
-    assert graph_has_legacy_ids([{"id": "setup", "source_file": "setup.py"}], root=".") is False
+    # sourceless / top-level file nodes don't false-positive
+    assert graph_has_legacy_ids([{"id": "setup", "source_file": "setup.py", "source_location": "L1"}], root=".") is False
     assert graph_has_legacy_ids([{"id": "x", "label": "y"}], root=".") is False
+    # package/dir-scoped SYMBOL ids (Go's _make_id(pkg_dir, name) -> "sub_thing") must
+    # NOT false-positive: not file-level (no L1), so ignored even though "sub_thing"
+    # coincides with the old file-stem form of pkg/sub/thing.go.
+    go_symbol = [{"id": "sub_thing", "source_file": "pkg/sub/thing.go", "type": "code", "source_location": "L3"}]
+    assert graph_has_legacy_ids(go_symbol, root=".") is False
 
 
 def test_semantic_rekey_relative_vs_absolute_source_file():