diff --git a/core/dr-catalog/src/faces.rs b/core/dr-catalog/src/faces.rs
index bbcaf14..cb2af93 100644
--- a/core/dr-catalog/src/faces.rs
+++ b/core/dr-catalog/src/faces.rs
@@ -556,6 +556,19 @@ impl FaceUpdate {
 /// bookkeeping: `face_shard::export_to_shards` re-exports an image whose
 /// marker is newer than the store's copy, which is how what was written
 /// here reaches the other devices.
+///
+/// It is re-written under the pipeline id the **faces carry**, not the one
+/// this pass ran as. `model_id` names the pass only through its embedder;
+/// the detector half of a marker is a statement about who drew the boxes,
+/// and this pass drew none. Every reader takes the two to agree: the export
+/// selects an image's faces by the marker's id, `marker_under` takes a
+/// marker as proof the detector has been over the image, and the shard
+/// store keys each face by it. When the marker was written as
+/// `scrfd_10g+w600k_mbf` over faces still spelled `w600k_mbf`, the export
+/// found no faces under it and sent the other devices an entry saying the
+/// thorough detector had looked and found nothing — over photographs with
+/// named faces on them. With no faces left, the pass's own id is the only
+/// one there is, and the marker says so.
 pub fn record_updates(
     conn: &Connection,
     image_id: ImageId,
@@ -602,13 +615,25 @@ pub fn record_updates(
     for f in dropped {
         tx.execute("DELETE FROM faces WHERE id = ?1", [f.0 as i64])?;
     }
-    let remaining: i64 = tx.query_row(
+    let (remaining, found_by): (i64, Option<String>) = tx.query_row(
         &format!(
-            "SELECT COUNT(*) FROM faces WHERE image_id = ?1 AND {} = ?2",
+            "SELECT COUNT(*), MIN(model_id) FROM faces WHERE image_id = ?1 AND {} = ?2",
             embedder_sql("model_id")
         ),
         rusqlite::params![image_id.0 as i64, embedder_of(model_id)],
-        |r| r.get(0),
+        |r| Ok((r.get(0)?, r.get(1)?)),
+    )?;
+    let marker = found_by.as_deref().unwrap_or(model_id);
+    // One marker per embedder: a stale one under another spelling would
+    // keep saying that detector had been here, which is the claim the
+    // faces' own id is now making in its place.
+    tx.execute(
+        &format!(
+            "DELETE FROM face_index
+              WHERE image_id = ?1 AND model_id != ?2 AND {} = ?3",
+            embedder_sql("model_id")
+        ),
+        rusqlite::params![image_id.0 as i64, marker, embedder_of(model_id)],
     )?;
     tx.execute(
         "INSERT INTO face_index (image_id, model_id, indexed_at, faces_found, source_edge)
@@ -619,7 +644,7 @@ pub fn record_updates(
              source_edge = excluded.source_edge",
         rusqlite::params![
             image_id.0 as i64,
-            model_id,
+            marker,
             now_secs(),
             remaining,
             source_edge as i64,
@@ -1557,7 +1582,7 @@ fn iou(a: (f32, f32, f32, f32), b: (f32, f32, f32, f32)) -> f32 {
     }
 }
 
-fn now_secs() -> i64 {
+pub(crate) fn now_secs() -> i64 {
     std::time::SystemTime::now()
         .duration_since(std::time::UNIX_EPOCH)
         .map(|d| d.as_secs() as i64)
@@ -1890,6 +1915,86 @@ mod tests {
         assert!(at >= marked_at, "the marker was not refreshed");
     }
 
+    /// The marker a per-face pass leaves names the detector that drew the
+    /// boxes, whatever pipeline the pass itself ran as. A marker under the
+    /// pass's id over faces spelled another way is one the export finds no
+    /// faces under — and it sent every other device "nothing here".
+    #[test]
+    fn an_update_keeps_the_marker_under_the_detector_that_found_the_faces() {
+        let c = db();
+        let img = image(&c, 1);
+        let ids = record_detections(
+            &c,
+            img,
+            "w600k_mbf",
+            1024,
+            &[DetectedFace {
+                quality: None,
+                ..face(1)
+            }],
+        )
+        .unwrap();
+        // The state V14 leaves: the faces, and no marker at all.
+        c.execute("DELETE FROM face_index", []).unwrap();
+
+        record_updates(
+            &c,
+            img,
+            "scrfd_10g+w600k_mbf",
+            6000,
+            &[FaceUpdate {
+                embedding: Some((vec![9; 1024], 21.5)),
+                ..FaceUpdate::for_face(ids[0])
+            }],
+            &[],
+        )
+        .unwrap();
+
+        let markers: Vec<(String, i64)> = c
+            .prepare("SELECT model_id, faces_found FROM face_index")
+            .unwrap()
+            .query_map([], |r| Ok((r.get(0)?, r.get(1)?)))
+            .unwrap()
+            .map(Result::unwrap)
+            .collect();
+        assert_eq!(markers, vec![("w600k_mbf".to_string(), 1)]);
+
+        // A marker already there under the pass's own id is replaced, not
+        // kept beside the right one.
+        c.execute(
+            "INSERT INTO face_index(image_id, model_id, indexed_at, faces_found, source_edge)
+             VALUES (1, 'scrfd_10g+w600k_mbf', 0, 0, 6000)",
+            [],
+        )
+        .unwrap();
+        record_updates(
+            &c,
+            img,
+            "scrfd_10g+w600k_mbf",
+            6000,
+            &[FaceUpdate {
+                crop: Some(vec![1, 2, 3]),
+                ..FaceUpdate::for_face(ids[0])
+            }],
+            &[],
+        )
+        .unwrap();
+        let n: i64 = c
+            .query_row("SELECT COUNT(*) FROM face_index", [], |r| r.get(0))
+            .unwrap();
+        assert_eq!(n, 1, "a second marker survived");
+
+        // With every face dropped there is no detector left to name, and
+        // the pass's own id records that it looked.
+        record_updates(&c, img, "scrfd_10g+w600k_mbf", 6000, &[], &ids).unwrap();
+        let marker: (String, i64) = c
+            .query_row("SELECT model_id, faces_found FROM face_index", [], |r| {
+                Ok((r.get(0)?, r.get(1)?))
+            })
+            .unwrap();
+        assert_eq!(marker, ("scrfd_10g+w600k_mbf".to_string(), 0));
+    }
+
     /// Re-detection is coalesced per image, so it must replace rather than
     /// append — otherwise every re-index doubles the library's face count.
     #[test]