diff --git a/.serena/memories/common/geometry-invariants.md b/.serena/memories/common/geometry-invariants.md
index f90475a285..b78034c242 100644
--- a/.serena/memories/common/geometry-invariants.md
+++ b/.serena/memories/common/geometry-invariants.md
@@ -20,6 +20,14 @@ After a geometric mutation, equivalent fields such as `:y`, `(:y :selrect)`, and
 - `gsh/transform-shape`: applies a full transform.
 - `cts/setup-shape`: initializes geometry for new shapes; variant test helpers such as `thv/add-variant-with-child` use it.
 
+## Flip flags through parent placement
+
+When composing a parent's orientation onto content, compose flip flags from
+the source shape and the origin/target parent frames. Matrix decomposition
+can set both flags during a large rotation, even when several smaller
+rotations authored neither flip (F170). Keep the original nil/false value
+when the parent frames do not change that axis's flip.
+
 ## Edits that break the invariant
 
 - `(assoc shape :x ...)` or `(assoc shape :y ...)`: updates only one field and leaves `:selrect` / `:points` stale.
@@ -45,4 +53,4 @@ Using `(ths/update-shape file label :y 101)` leaves `:selrect.y` stale. Downstre
 
 When a copy shape changes geometry through the proper pipeline (`set-shape-attr` via `process-operation :set`), `:touched` gains `:geometry-group` unless ignored. Tests can either drive the production update with `cls/generate-update-shapes`, or inject `(assoc shape :touched #{:geometry-group})` when only touched state matters.
 
-If a test needs both a new position and touched state, move the shape first with geometry-preserving helpers, then inject or assert touched state.
\ No newline at end of file
+If a test needs both a new position and touched state, move the shape first with geometry-preserving helpers, then inject or assert touched state.
diff --git a/common/src/app/common/logic/libraries.cljc b/common/src/app/common/logic/libraries.cljc
index 870d71730b..4816bf7b0d 100644
--- a/common/src/app/common/logic/libraries.cljc
+++ b/common/src/app/common/logic/libraries.cljc
@@ -276,10 +276,16 @@
       main-container
       (let [transform (gmt/transform-in (gsh/shape->center shape-main) relative)
             angle (- (or (:rotation target) 0) (or (:rotation origin) 0))
-            turn #(-> %
-                      (assoc-in [:modifiers :rotation] angle)
-                      (gsh/apply-transform transform)
-                      (dissoc :modifiers))]
+            flip (fn [shape key]
+                   (cond-> (get shape key)
+                     (not= (boolean (get origin key)) (boolean (get target key))) not))
+            turn (fn [shape]
+                   (-> shape
+                       (assoc-in [:modifiers :rotation] angle)
+                       (gsh/apply-transform transform)
+                       (dissoc :modifiers)
+                       (assoc :flip-x (flip shape :flip-x)
+                              :flip-y (flip shape :flip-y))))]
         (update main-container :objects
                 (fn [objects]
                   (reduce #(update %1 %2 turn) objects
diff --git a/common/test/common_tests/logic/comp_expected_geometry_test.cljc b/common/test/common_tests/logic/comp_expected_geometry_test.cljc
index 559a35b550..60fc908de1 100644
--- a/common/test/common_tests/logic/comp_expected_geometry_test.cljc
+++ b/common/test/common_tests/logic/comp_expected_geometry_test.cljc
@@ -213,3 +213,18 @@
         after (get-in (thf/current-page synced) [:objects (:id child)])]
     (t/is (= (select-keys child [:flip-x :flip-y]) (select-keys after [:flip-x :flip-y])))
     (t/is (gsh/close-attrs? :points (:points child) (:points after) 0.001))))
+
+(t/deftest update-main-keeps-child-flips-when-syncing-through-a-rotated-parent
+  (let [updated (-> (setup/nested-component-with-copy)
+                    (r/step (n/rotate :copy-root 45)) r/settle
+                    (r/step (n/rotate :copy-root 90)) r/settle
+                    (r/step (n/update-main :copy-root)) r/settle)
+        file (tm/file updated)
+        main (tm/resolve-shape updated :main2-nested-head)
+        child (tm/shape-by-id updated (first (:shapes main)))
+        synced (:file (r/sync-cascade file {} (keys (get-in file [:data :components]))))]
+    (doseq [shape [main child]]
+      (let [after (ths/get-shape-by-id synced (:id shape))
+            flips #(mapv (comp boolean %) [:flip-x :flip-y])]
+        (t/is (= (flips shape) (flips after)))
+        (t/is (gsh/close-attrs? :points (:points shape) (:points after) 0.001))))))