diff --git a/excalidraw-app/App.tsx b/excalidraw-app/App.tsx
index 8ba4f5fe..56779e0a 100644
--- a/excalidraw-app/App.tsx
+++ b/excalidraw-app/App.tsx
@@ -545,7 +545,7 @@ const ExcalidrawWrapper = () => {
   const saveToPds = useCallback(() => {
     if (atprotoAuth && activeScene && excalidrawAPI) {
       scheduleAutosave(
-        excalidrawAPI.getSceneElements(),
+        excalidrawAPI.getSceneElementsIncludingDeleted(),
         excalidrawAPI.getAppState(),
         excalidrawAPI.getFiles(),
       );
diff --git a/excalidraw-app/data/atproto/activeScene.ts b/excalidraw-app/data/atproto/activeScene.ts
index 572f9ff2..c99c9e90 100644
--- a/excalidraw-app/data/atproto/activeScene.ts
+++ b/excalidraw-app/data/atproto/activeScene.ts
@@ -108,6 +108,7 @@ export const isAtprotoLink = (link: string) => {
 };
 
 type SaveArgs = {
+  /** Must include soft-deleted elements — see the `elements` doc in saveScene's options (scenes.ts). */
   elements: readonly OrderedExcalidrawElement[];
   appState: Partial<AppState>;
   files: BinaryFiles;
diff --git a/excalidraw-app/data/atproto/scenes.ts b/excalidraw-app/data/atproto/scenes.ts
index 47c26a68..06b131d3 100644
--- a/excalidraw-app/data/atproto/scenes.ts
+++ b/excalidraw-app/data/atproto/scenes.ts
@@ -161,6 +161,15 @@ export const saveScene = async (
     lastBlobCid,
     swapCid,
   }: {
+    /**
+     * Must include soft-deleted (tombstone) elements — i.e. the caller should
+     * pass `getSceneElementsIncludingDeleted()`, not `getSceneElements()`. The
+     * blob-CID dedupe above compares `serializeAsJSON` output across call
+     * sites (autosave vs. manual save vs. viewing snapshots), so passing a
+     * differently-filtered element set here produces a different CID and
+     * defeats the skip check with a redundant uploadBlob. Tombstones are also
+     * required for `reconcileElements` in the CAS merge path below.
+     */
     elements: readonly OrderedExcalidrawElement[];
     appState: Partial<AppState>;
     files: BinaryFiles;
diff --git a/excalidraw-app/data/atproto/viewingActions.ts b/excalidraw-app/data/atproto/viewingActions.ts
index 38bc0309..c8534f7f 100644
--- a/excalidraw-app/data/atproto/viewingActions.ts
+++ b/excalidraw-app/data/atproto/viewingActions.ts
@@ -32,7 +32,7 @@ export const enterViewing = async (
   // sketches
   if (!appJotaiStore.get(preViewSnapshotAtom)) {
     appJotaiStore.set(preViewSnapshotAtom, {
-      elements: excalidrawAPI.getSceneElements(),
+      elements: excalidrawAPI.getSceneElementsIncludingDeleted(),
       appState: excalidrawAPI.getAppState(),
       files: excalidrawAPI.getFiles(),
       activeScene: appJotaiStore.get(activeSceneAtom),
@@ -117,7 +117,7 @@ export const saveACopy = async (excalidrawAPI: ExcalidrawImperativeAPI) => {
   }
 
   const saved = await saveScene(auth.agent, {
-    elements: excalidrawAPI.getSceneElements(),
+    elements: excalidrawAPI.getSceneElementsIncludingDeleted(),
     appState: excalidrawAPI.getAppState(),
     files: excalidrawAPI.getFiles(),
     name: `Copy of ${viewing.name}`,
diff --git a/excalidraw-app/share/ShareDialog.tsx b/excalidraw-app/share/ShareDialog.tsx
index c919ba93..2a2a4948 100644
--- a/excalidraw-app/share/ShareDialog.tsx
+++ b/excalidraw-app/share/ShareDialog.tsx
@@ -102,7 +102,7 @@ const SaveToPdsContent = ({ handleClose }: { handleClose: () => void }) => {
     try {
       trackEvent("share", "save to pds");
       const saved = await saveScene(auth.agent, {
-        elements: excalidrawAPI.getSceneElements(),
+        elements: excalidrawAPI.getSceneElementsIncludingDeleted(),
         appState: excalidrawAPI.getAppState(),
         files: excalidrawAPI.getFiles(),
         name,
diff --git a/excalidraw-app/tests/atprotoScenes.test.ts b/excalidraw-app/tests/atprotoScenes.test.ts
index 8e8843c7..cbd249cc 100644
--- a/excalidraw-app/tests/atprotoScenes.test.ts
+++ b/excalidraw-app/tests/atprotoScenes.test.ts
@@ -1,7 +1,9 @@
 import { describe, expect, it, vi } from "vitest";
 
+import { serializeAsJSON } from "@excalidraw/excalidraw/data/json";
 import { API } from "@excalidraw/excalidraw/tests/helpers/api";
 
+import { computeSceneBlobCid } from "../data/atproto/blobCid";
 import { compressSceneJson } from "../data/atproto/compression";
 import { saveScene } from "../data/atproto/scenes";
 
@@ -288,3 +290,93 @@ describe("saveScene compare-and-swap", () => {
     expect(saved?.cid).toBe("createcid");
   });
 });
+
+describe("saveScene dedupe with tombstones", () => {
+  // Regression test: callers must pass elements INCLUDING deleted ones. The
+  // blob-CID dedupe check (scenes.ts) compares serializeAsJSON output across
+  // call sites — if one call site passes non-deleted-only elements while
+  // another (e.g. a later autosave) passes elements including deleted, the
+  // computed CIDs differ and the skip check never fires, causing a redundant
+  // uploadBlob. Tombstones are also required by reconcileElements on the CAS
+  // merge path.
+  it("skips the second uploadBlob when the same elements (incl. a tombstone) are saved twice", async () => {
+    const { agent, uploadBlob, putRecord, createRecord } = createFakeAgent();
+
+    const elementsIncludingDeleted = [
+      API.createElement({ id: "visible1", index: "a1" as any }),
+      API.createElement({
+        id: "deleted1",
+        index: "a2" as any,
+        isDeleted: true,
+      }),
+    ];
+
+    const first = await saveScene(agent, {
+      elements: elementsIncludingDeleted as any,
+      appState: {},
+      files: {},
+      name: "Test drawing",
+    });
+    expect(first).not.toBeNull();
+    expect(first?.blobCid).toMatch(/^bafkrei[a-z2-7]{52}$/);
+
+    uploadBlob.mockClear();
+    putRecord.mockClear();
+    createRecord.mockClear();
+
+    // same elements (still including the tombstone), same rkey + lastBlobCid
+    // seeded from the first save's result — must be a no-op
+    const second = await saveScene(agent, {
+      elements: elementsIncludingDeleted as any,
+      appState: {},
+      files: {},
+      name: "Test drawing",
+      rkey: first!.rkey,
+      lastBlobCid: first!.blobCid,
+    });
+
+    expect(second).toBeNull();
+    expect(uploadBlob).not.toHaveBeenCalled();
+    expect(putRecord).not.toHaveBeenCalled();
+    expect(createRecord).not.toHaveBeenCalled();
+  });
+
+  it("computes a different blob CID when the tombstone is dropped", async () => {
+    const elementsIncludingDeleted = [
+      API.createElement({ id: "visible1", index: "a1" as any }),
+      API.createElement({
+        id: "deleted1",
+        index: "a2" as any,
+        isDeleted: true,
+      }),
+    ];
+    const elementsExcludingDeleted = elementsIncludingDeleted.filter(
+      (el) => !el.isDeleted,
+    );
+
+    const jsonWithTombstone = serializeAsJSON(
+      elementsIncludingDeleted as any,
+      {} as any,
+      {},
+      "database",
+    );
+    const jsonWithoutTombstone = serializeAsJSON(
+      elementsExcludingDeleted as any,
+      {} as any,
+      {},
+      "database",
+    );
+
+    const cidWithTombstone = await computeSceneBlobCid(jsonWithTombstone);
+    const cidWithoutTombstone = await computeSceneBlobCid(
+      jsonWithoutTombstone,
+    );
+
+    // proves why every saveScene call site must pass elements including
+    // deleted: a caller that filters tombstones out produces a different CID,
+    // which defeats the dedupe check against a call site that doesn't filter
+    expect(cidWithTombstone).not.toBeNull();
+    expect(cidWithoutTombstone).not.toBeNull();
+    expect(cidWithTombstone).not.toBe(cidWithoutTombstone);
+  });
+});
diff --git a/lexicons/app/lexidraw/scene.json b/lexicons/app/lexidraw/scene.json
index f4d0ae57..74c5cc22 100644
--- a/lexicons/app/lexidraw/scene.json
+++ b/lexicons/app/lexidraw/scene.json
@@ -4,7 +4,7 @@
   "defs": {
     "main": {
       "type": "record",
-      "description": "An Excalidraw drawing. The full scene (elements, appState and embedded image files as dataURLs) is stored as a JSON blob",
+      "description": "An Excalidraw drawing. The full scene (elements, appState and embedded image files as dataURLs) is stored as a gzipped JSON blob",
       "key": "tid",
       "record": {
         "type": "object",