diff --git a/crates/engine/src/lib.rs b/crates/engine/src/lib.rs
index f472d7b60..e60cf5cf8 100644
--- a/crates/engine/src/lib.rs
+++ b/crates/engine/src/lib.rs
@@ -874,14 +874,16 @@ impl Session {
     /// undo step; otherwise it is committed with a history entry.
     pub fn set_develop(&mut self, id: PhotoId, settings: DevelopSettings, label: &str) -> Result<()> {
         let now = (self.clock)();
-        let settings = Arc::new(self.fit_constrained_crop(id, settings));
+        // Auto Sync carries the edit as asked; each photo then fits its own crop (review of #1990)
+        let requested = settings;
+        let settings = Arc::new(self.fit_constrained_crop(id, requested.clone()));
         if let Some(i) = &self.interaction
             && i.photo == id
         {
             return self.apply_silent(Op::SetDevelop { id, settings, label: label.into(), edited: Some(now) });
         }
         let mut ops = vec![self.develop_op(id, (*settings).clone(), label).ok_or(lightcraft_catalog::CatalogError::NoPhoto(id))?];
-        ops.extend(self.auto_sync_ops(id, &settings, label));
+        ops.extend(self.auto_sync_ops(id, &requested, label));
         let op = if ops.len() == 1 { ops.remove(0) } else { Op::Batch { ops } };
         self.commit(label, op)
     }
@@ -917,10 +919,11 @@ impl Session {
         d
     }
 
-    /// With Auto Sync on, the ops that carry an edit of the active photo `id` (to `new`) over to the
-    /// other selected photos: only the settings that changed; never spot removal or red eye (they
-    /// belong to one photo's pixels), nor the rendering process (Sync doesn't carry it either), nor
-    /// history / snapshot restores.
+    /// With Auto Sync on, the ops that carry an edit of the active photo `id` (to `new`, as asked,
+    /// before its crop is fitted) over to the other selected photos: only the settings that changed;
+    /// never spot removal or red eye (they belong to one photo's pixels), nor the rendering process
+    /// (Sync doesn't carry it either), nor history / snapshot restores. Constrain Crop then fits each
+    /// photo's own crop: the active photo's fitted crop is never copied over another's.
     fn auto_sync_ops(&self, id: PhotoId, new: &DevelopSettings, label: &str) -> Vec<Op> {
         if !self.auto_sync
             || self.active() != Some(id)
@@ -946,7 +949,7 @@ impl Session {
             .filter(|x| **x != id)
             .filter_map(|x| self.develop_of(*x).map(|d| (*x, d)))
             .filter_map(|(x, d)| {
-                let synced = lightcraft_develop::apply_partial(&d, &delta, 1.0);
+                let synced = self.fit_constrained_crop(x, lightcraft_develop::apply_partial(&d, &delta, 1.0));
                 (synced != *d).then(|| self.develop_op(x, synced, label)).flatten()
             })
             .collect()
diff --git a/crates/engine/src/tests_constrain_crop.rs b/crates/engine/src/tests_constrain_crop.rs
index 37c6d734d..51dcee1c0 100644
--- a/crates/engine/src/tests_constrain_crop.rs
+++ b/crates/engine/src/tests_constrain_crop.rs
@@ -70,3 +70,31 @@ fn a_crop_drawn_by_hand_is_kept_as_drawn() {
     s.execute("crop.set", &json!({"rect": [0.0, 0.0, 1.0, 1.0]})).unwrap();
     assert_eq!(crop(&s).rect, Rect::new(0.0, 0.0, 1.0, 1.0), "the crop edit itself is not refitted");
 }
+
+/// Review of #1990: with Auto Sync, a Geometry edit on the active photo fits each selected photo's
+/// own crop; the active photo's fitted crop is never copied over another photo's (smaller) crop.
+#[test]
+fn auto_sync_fits_each_photos_own_crop() {
+    let mut s = Session::with_demo();
+    let ids: Vec<_> = s.catalog.photos().take(2).map(|p| p.id).collect();
+    let (a, b) = (ids[0], ids[1]);
+    // B: a small crop off-centre; both constrained
+    s.selection = crate::Selection { ids: vec![b], active: Some(b) };
+    s.execute("crop.set", &json!({"rect": [0.05, 0.1, 0.45, 0.5]})).unwrap();
+    constrain(&mut s, true);
+    s.selection = crate::Selection { ids: vec![a], active: Some(a) };
+    constrain(&mut s, true);
+    let b_before = s.develop_of(b).unwrap().crop.geometry.rect;
+    // A active, both selected, Auto Sync on: a Geometry edit on A
+    s.selection = crate::Selection { ids: vec![a, b], active: Some(a) };
+    s.execute("develop.autoSync", &json!({"on": true})).unwrap();
+    vertical(&mut s, -60.0);
+    let (da, db) = (s.develop_of(a).unwrap(), s.develop_of(b).unwrap());
+    assert_eq!(db.geometry.vertical, -60.0, "the edit reached B");
+    let b_after = db.crop.geometry.rect;
+    assert_ne!(b_after, da.crop.geometry.rect, "B keeps a crop of its own");
+    let inside = |r: Rect, o: Rect| r.x0 >= o.x0 - 1e-9 && r.y0 >= o.y0 - 1e-9 && r.x1 <= o.x1 + 1e-9 && r.y1 <= o.y1 + 1e-9;
+    assert!(inside(b_after, b_before), "B's crop only shrinks within itself: {b_before:?} -> {b_after:?}");
+    s.selection = crate::Selection { ids: vec![b], active: Some(b) };
+    assert!(fits(&s), "and fits B's warp");
+}