diff --git a/CHANGELOG.md b/CHANGELOG.md
index c97617cd885..35f63bf5185 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -120,6 +120,7 @@ Docs: https://docs.openclaw.ai
 - Onboarding/custom providers: store Azure OpenAI and Azure AI Foundry custom endpoints with the Responses API config shape, normalized `/openai/v1` base URLs, and Azure-safe defaults so TUI and agent runs work after setup. (#49543) Thanks @kunalk16.
 - Docker/live tests: mount external CLI auth homes into writable container copies, derive Codex OAuth expiry from JWT `exp`, refresh synced CLI creds instead of trusting stale cached expiry, and make gateway live probes wait on transcript output so `pnpm test:docker:all` stays green in Linux.
 - Plugins/install precedence: keep bundled plugins ahead of auto-discovered globals by default, but let an explicitly installed plugin record win its own duplicate-id tie so installed channel plugins load from `~/.openclaw/extensions` after `openclaw plugins install`. (#46722) Thanks @Takhoffman.
+- Agents/memory flush: keep transcript-hash dedup active across memory-flush fallback retries so a write-then-throw flush attempt cannot append duplicate `MEMORY.md` entries before the fallback cycle completes. (#34222) Thanks @lml2468.
 - Control UI/logging: make browser-safe logger imports avoid eager temp-dir resolution so the bundled Control UI no longer crashes to a blank screen when logging reaches `tmp-openclaw-dir`. (#48469) Fixes #48062. Thanks @7inspire.
 - Plugins/scoped ids: preserve scoped plugin ids during install and config keying, and keep bundled plugins ahead of discovered duplicate ids by default so `@scope/name` plugins no longer collide with unscoped installs. (#47413) Thanks @vincentkoc.
 - Gateway/watch mode: restart on bundled-plugin package and manifest metadata changes, rebuild `dist` for extension source and `tsdown.config.ts` changes, and still ignore extension docs. (#47571) Thanks @gumadeiras.
diff --git a/src/auto-reply/reply/agent-runner-memory.ts b/src/auto-reply/reply/agent-runner-memory.ts
index c6b36eb0029..78cba1d6d44 100644
--- a/src/auto-reply/reply/agent-runner-memory.ts
+++ b/src/auto-reply/reply/agent-runner-memory.ts
@@ -507,6 +507,7 @@ export async function runMemoryFlushIfNeeded(params: {
     });
   }
   let memoryCompactionCompleted = false;
+  let fallbackFlushAttemptedForCurrentHash = false;
   const memoryFlushNowMs = Date.now();
   const memoryFlushWritePath = resolveMemoryFlushRelativePathForRun({
     cfg: params.cfg,
@@ -523,6 +524,16 @@ export async function runMemoryFlushIfNeeded(params: {
       ...resolveModelFallbackOptions(params.followupRun.run),
       runId: flushRunId,
       run: async (provider, model, runOptions) => {
+        if (contextHashBeforeFlush && fallbackFlushAttemptedForCurrentHash) {
+          logVerbose(
+            `memoryFlush fallback candidate skipped (context hash already attempted): sessionKey=${params.sessionKey} hash=${contextHashBeforeFlush} provider=${provider} model=${model}`,
+          );
+          // A prior candidate already attempted this exact flush context. Be
+          // conservative and skip later candidates so a write-then-throw failure
+          // cannot append the same memory twice during a single fallback cycle.
+          return { payloads: [], meta: {} };
+        }
+        fallbackFlushAttemptedForCurrentHash = Boolean(contextHashBeforeFlush);
         const { embeddedContext, senderContext, runBaseParams } = buildEmbeddedRunExecutionParams({
           run: params.followupRun.run,
           sessionCtx: params.sessionCtx,
diff --git a/src/auto-reply/reply/agent-runner.runreplyagent.e2e.test.ts b/src/auto-reply/reply/agent-runner.runreplyagent.e2e.test.ts
index ce4d5bae9e5..e84877aaf54 100644
--- a/src/auto-reply/reply/agent-runner.runreplyagent.e2e.test.ts
+++ b/src/auto-reply/reply/agent-runner.runreplyagent.e2e.test.ts
@@ -31,7 +31,10 @@ type EmbeddedRunParams = {
   memoryFlushWritePath?: string;
   bootstrapPromptWarningSignaturesSeen?: string[];
   bootstrapPromptWarningSignature?: string;
-  onAgentEvent?: (evt: { stream?: string; data?: { phase?: string; willRetry?: boolean } }) => void;
+  onAgentEvent?: (evt: {
+    stream?: string;
+    data?: { phase?: string; willRetry?: boolean; completed?: boolean };
+  }) => void;
 };
 
 const state = vi.hoisted(() => ({
@@ -2032,6 +2035,121 @@ describe("runReplyAgent memory flush", () => {
     });
   });
 
+  it("skips duplicate memory writes across memory-flush fallback retries", async () => {
+    await withTempStore(async (storePath) => {
+      const sessionKey = "main";
+      const sessionFile = "session-relative.jsonl";
+      const fixtureDir = path.dirname(storePath);
+      const transcriptPath = path.join(fixtureDir, sessionFile);
+      await fs.mkdir(path.dirname(transcriptPath), { recursive: true });
+      await fs.writeFile(
+        transcriptPath,
+        [
+          JSON.stringify({ message: { role: "user", content: "Remember alpha." } }),
+          JSON.stringify({ message: { role: "assistant", content: "Stored alpha." } }),
+        ].join("\n") + "\n",
+        "utf-8",
+      );
+
+      const sessionEntry = {
+        sessionId: "session",
+        updatedAt: Date.now(),
+        sessionFile,
+        totalTokens: 80_000,
+        compactionCount: 1,
+      };
+
+      await seedSessionStore({ storePath, sessionKey, entry: sessionEntry });
+
+      let flushAttemptCount = 0;
+      let memoryFilePath: string | undefined;
+      const prompts: string[] = [];
+      state.runEmbeddedPiAgentMock.mockImplementation(async (params: EmbeddedRunParams) => {
+        prompts.push(params.prompt ?? "");
+        if (params.prompt?.includes("Pre-compaction memory flush.")) {
+          flushAttemptCount += 1;
+          memoryFilePath = path.join(fixtureDir, params.memoryFlushWritePath ?? "memory/flush.md");
+          await fs.mkdir(path.dirname(memoryFilePath), { recursive: true });
+          await fs.appendFile(memoryFilePath, "remember alpha\n", "utf-8");
+          if (flushAttemptCount === 1) {
+            throw new Error("flush failed after write");
+          }
+          return { payloads: [], meta: {} };
+        }
+        return {
+          payloads: [{ text: "ok" }],
+          meta: { agentMeta: { usage: { input: 1, output: 1 } } },
+        };
+      });
+
+      const fallbackSpy = vi
+        .spyOn(modelFallbackModule, "runWithModelFallback")
+        .mockImplementationOnce(
+          async ({
+            provider,
+            model,
+            run,
+          }: {
+            provider: string;
+            model: string;
+            run: (provider: string, model: string) => Promise<unknown>;
+          }) => {
+            try {
+              await run(provider, model);
+            } catch {
+              // Simulate advancing to the next fallback candidate after the first
+              // memory flush attempt already wrote and then failed.
+            }
+            return {
+              result: await run("openai", "gpt-5.4"),
+              provider: "openai",
+              model: "gpt-5.4",
+              attempts: [
+                {
+                  provider,
+                  model,
+                  error: "flush failed after write",
+                  reason: "unknown",
+                },
+              ],
+            };
+          },
+        );
+
+      try {
+        const baseRun = createBaseRun({
+          storePath,
+          sessionEntry,
+          runOverrides: {
+            sessionFile,
+            workspaceDir: fixtureDir,
+          },
+        });
+
+        await runReplyAgentWithBase({
+          baseRun,
+          storePath,
+          sessionKey,
+          sessionEntry,
+          commandBody: "hello",
+        });
+      } finally {
+        fallbackSpy.mockRestore();
+      }
+
+      expect(flushAttemptCount).toBe(1);
+      expect(
+        prompts.filter((prompt) => prompt.includes("Pre-compaction memory flush.")),
+      ).toHaveLength(1);
+      expect(memoryFilePath).toBeDefined();
+      await expect(fs.readFile(memoryFilePath!, "utf-8")).resolves.toBe("remember alpha\n");
+
+      const stored = JSON.parse(await fs.readFile(storePath, "utf-8"));
+      expect(stored[sessionKey].memoryFlushAt).toBeTypeOf("number");
+      expect(stored[sessionKey].memoryFlushContextHash).toMatch(/^[0-9a-f]{16}$/);
+    });
+  });
+
   it("increments compaction count when flush compaction completes", async () => {
     await withTempStore(async (storePath) => {
       const sessionKey = "main";