diff --git a/scripts/profile_sync.py b/scripts/profile_sync.py
index 421395c1..23963cc6 100644
--- a/scripts/profile_sync.py
+++ b/scripts/profile_sync.py
@@ -815,9 +815,14 @@ def anchor_part(
         # the old path at the pin, which is why that one is tried first.
         pin_lines = fetch(PIN, path, part.start, tokens)
     if pin_lines is None:
-        return PartResult(
-            part, "GONE", None, None, None, [], "pin revision missing", slug, url
-        )
+        # Present at HEAD, absent at the pin, and the cited range fits the
+        # HEAD file: the ref was written against HEAD while source_commit
+        # still names an older revision. Saying "missing" sends the reader
+        # hunting for a move that never happened; the fix is the pin.
+        reason = "pin revision missing"
+        if head_lines is not None and part.start <= len(head_lines):
+            reason = "written against HEAD, pin names an older revision"
+        return PartResult(part, "GONE", None, None, None, [], reason, slug, url)
 
     end = part.end or part.start
     anchored = anchor_block(pin_lines, head_lines, part.start, end)
diff --git a/tests/test_profile_sync.py b/tests/test_profile_sync.py
index 9af5227b..ab46d728 100644
--- a/tests/test_profile_sync.py
+++ b/tests/test_profile_sync.py
@@ -1435,6 +1435,39 @@ def _sample_report():
     )
 
 
+class TestRefsAheadOfTheirPin(TestBuildReport):
+    """Say when a ref describes HEAD and the pin still names an older tree.
+
+    Reprofiling against HEAD and forgetting to advance source_commit leaves
+    the profile describing two revisions at once. The symptom was "pin
+    revision missing", which reads as code that vanished and sends the
+    reader hunting for a move that never happened. The cause is the pin.
+    """
+
+    def test_present_at_head_and_absent_at_the_pin_names_the_pin(self):
+        self.files[("headsha", "a.c")] = ["x", "the cited line", "y"]
+        report = build_report("test", self._profile(["a.c:2"]), self.dir)
+        part = report.entries[0].parts[0]
+        self.assertEqual(part.status, "GONE")
+        self.assertEqual(
+            part.reason, "written against HEAD, pin names an older revision"
+        )
+
+    def test_a_range_beyond_head_is_still_just_missing(self):
+        """Not every pin miss is a stale pin; only one that fits HEAD."""
+        self.files[("headsha", "a.c")] = ["x"]
+        report = build_report("test", self._profile(["a.c:40"]), self.dir)
+        part = report.entries[0].parts[0]
+        self.assertEqual(part.status, "GONE")
+        self.assertNotEqual(
+            part.reason, "written against HEAD, pin names an older revision"
+        )
+
+    def test_a_file_missing_from_both_is_unchanged(self):
+        report = build_report("test", self._profile(["ghost.c:2"]), self.dir)
+        self.assertEqual(report.entries[0].parts[0].status, "GONE")
+
+
 class TestBareNameResolvedAtThePin(TestBuildReport):
     """A bare filename belongs to the revision the ref was written against.