diff --git a/common/src/app/common/geom/shapes/flex_layout/params.cljc b/common/src/app/common/geom/shapes/flex_layout/params.cljc
index 57a1fab63d..0d7d67ba1b 100644
--- a/common/src/app/common/geom/shapes/flex_layout/params.cljc
+++ b/common/src/app/common/geom/shapes/flex_layout/params.cljc
@@ -88,8 +88,8 @@
            parent-selrect (:selrect parent)
 
            padding (when (and (not (nil? parent)) (> (count shapes) 0))
-                     {:p1 (- min-y (:y1 parent-selrect))
-                      :p2 (- min-x (:x1 parent-selrect))})]
+                     {:p1 (max 0 (- min-y (:y1 parent-selrect)))
+                      :p2 (max 0 (- min-x (:x1 parent-selrect)))})]
 
        (cond-> {:layout-flex-dir direction :layout-gap layout-gap}
          (not (nil? padding))
diff --git a/common/src/app/common/geom/shapes/grid_layout/params.cljc b/common/src/app/common/geom/shapes/grid_layout/params.cljc
index ee3a779942..e310dfadd1 100644
--- a/common/src/app/common/geom/shapes/grid_layout/params.cljc
+++ b/common/src/app/common/geom/shapes/grid_layout/params.cljc
@@ -154,8 +154,8 @@
            layout-grid-columns (mapv (constantly ctl/default-track-value) cols)
 
            parent-childs-vector (gpt/to-vec (gpo/origin (:points parent)) (gpt/point all-shapes-rect))
-           p-left (:x parent-childs-vector)
-           p-top  (:y parent-childs-vector)]
+           p-left (max 0 (:x parent-childs-vector))
+           p-top  (max 0 (:y parent-childs-vector))]
 
        (-> {:layout-grid-columns layout-grid-columns
             :layout-grid-rows layout-grid-rows
diff --git a/common/test/common_tests/geom_flex_layout_test.cljc b/common/test/common_tests/geom_flex_layout_test.cljc
index c016daeea7..4e6f6a149c 100644
--- a/common/test/common_tests/geom_flex_layout_test.cljc
+++ b/common/test/common_tests/geom_flex_layout_test.cljc
@@ -7,6 +7,7 @@
 (ns common-tests.geom-flex-layout-test
   (:require
    [app.common.geom.rect :as grc]
+   [app.common.geom.shapes.flex-layout.params :as flparams]
    [app.common.geom.shapes.flex-layout.positions :as flp]
    [app.common.math :as mth]
    [app.common.types.shape :as cts]
@@ -104,3 +105,33 @@
                                   :layout-justify-content :end
                                   :x 0 :y 0 :width 100 :height 100})]
       (t/is (not (ctl/v-end? frame))))))
+
+;; ---- calculate-params paddings ----
+;;
+;; Adding a flex layout derives the paddings from the distance between the
+;; board and its children. A child that overflows the board, or floating
+;; point noise after "Resize board to fit content", gave negative paddings
+;; that the shape schema rejects, which broke autosave (#12107).
+
+(defn- params-for-child
+  [child-attrs]
+  (let [parent (cts/setup-shape {:type :frame :x 0 :y 0 :width 100 :height 100})
+        child  (cts/setup-shape (merge {:type :rect :parent-id (:id parent)} child-attrs))
+        parent (assoc parent :shapes [(:id child)])
+        objects {(:id parent) parent (:id child) child}]
+    (flparams/calculate-params objects [child] parent)))
+
+(t/deftest calculate-params-keeps-positive-padding
+  (t/is (= {:p1 20 :p2 10 :p3 20 :p4 10}
+           (:layout-padding (params-for-child {:x 10 :y 20 :width 50 :height 50})))))
+
+(t/deftest calculate-params-clamps-overflowing-child-padding
+  (t/is (= {:p1 0 :p2 0 :p3 0 :p4 0}
+           (:layout-padding (params-for-child {:x -10 :y -5 :width 150 :height 150})))))
+
+(t/deftest calculate-params-clamps-float-noise-padding
+  (let [padding (:layout-padding
+                 (params-for-child {:x -1.1728368917829357E-5
+                                    :y -2.1457672119140625E-6
+                                    :width 100 :height 100}))]
+    (t/is (every? #(not (neg? %)) (vals padding)))))
diff --git a/common/test/common_tests/geom_grid_layout_test.cljc b/common/test/common_tests/geom_grid_layout_test.cljc
index 1769ab634a..ac642b2d43 100644
--- a/common/test/common_tests/geom_grid_layout_test.cljc
+++ b/common/test/common_tests/geom_grid_layout_test.cljc
@@ -11,6 +11,7 @@
    [app.common.geom.modifiers]
    [app.common.geom.rect :as grc]
    [app.common.geom.shapes.grid-layout.layout-data :as gld]
+   [app.common.geom.shapes.grid-layout.params :as glparams]
    [app.common.math :as mth]
    [app.common.types.shape :as cts]
    [clojure.test :as t]))
@@ -408,3 +409,27 @@
           result (gld/set-auto-multi-span (auto-col-parent) tracks cmap cells frame-bounds {} :column)]
       (t/is (mth/close? 100.0 (:size (nth result 0)) 0.001))
       (t/is (mth/close? 100.0 (:size (nth result 1)) 0.001)))))
+
+;; ---------------------------------------------------------------------------
+;; calculate-params: derived paddings are never negative
+;; ---------------------------------------------------------------------------
+;;
+;; Adding a grid layout derives the paddings from the children. A child that
+;; overflows the board gave negative paddings that the shape schema rejects,
+;; which broke autosave (#12107).
+
+(defn- grid-params-for-children
+  [& children-attrs]
+  (let [parent   (cts/setup-shape {:type :frame :x 0 :y 0 :width 100 :height 100})
+        children (mapv #(cts/setup-shape (merge {:type :rect :parent-id (:id parent)} %))
+                       children-attrs)]
+    (glparams/calculate-params nil children parent)))
+
+(t/deftest grid-calculate-params-keeps-positive-padding
+  (let [params (grid-params-for-children {:x 10 :y 20 :width 30 :height 30})]
+    (t/is (mth/close? 20 (get-in params [:layout-padding :p1])))
+    (t/is (mth/close? 10 (get-in params [:layout-padding :p2])))))
+
+(t/deftest grid-calculate-params-clamps-overflowing-child-padding
+  (let [params (grid-params-for-children {:x -10 :y -5 :width 150 :height 150})]
+    (t/is (= {:p1 0 :p2 0 :p3 0 :p4 0} (:layout-padding params)))))