diff --git a/apps/booskiff-web/bff/auth-real.test.ts b/apps/booskiff-web/bff/auth-real.test.ts
index cf14ab3..6b699fd 100644
--- a/apps/booskiff-web/bff/auth-real.test.ts
+++ b/apps/booskiff-web/bff/auth-real.test.ts
@@ -60,7 +60,7 @@ test("returns OAuth next URL and Kratos cookies without an app session when logi
   // Then: OAuth 開始 URL と Kratos cookie のみを返す。
   expect(response?.status).toBe(200);
   expect(await response?.json()).toEqual({
-    authenticated: true, username: "alice@example.test", next: "/auth/oauth/start?return_to=/login",
+    authenticated: true, username: "alice@example.test", next: "/auth/oauth/start?return_to=/drive",
   });
   expect(response?.headers.getSetCookie().some((cookie) => cookie.startsWith("ory_kratos_session="))).toBe(true);
   expect(response?.headers.getSetCookie().some((cookie) => cookie.startsWith("booskiff_session="))).toBe(false);
diff --git a/apps/booskiff-web/bff/auth-real.ts b/apps/booskiff-web/bff/auth-real.ts
index b6bd808..bd2f57c 100644
--- a/apps/booskiff-web/bff/auth-real.ts
+++ b/apps/booskiff-web/bff/auth-real.ts
@@ -112,8 +112,9 @@ export async function realLogin(req: Request, config: RealAuthConfig, adapter: S
     const headers = new Headers({ "Content-Type": "application/json" });
     jar.applyToResponse(headers);
     // XHR は 302 で cross-origin Hydra chain を進められないため、トップレベル遷移用 URL を渡す。
-    // return_to=/login は #19 の SPA 経路回避策。修正後に /drive へ戻すことを再検討する。
-    return new Response(JSON.stringify({ authenticated: true, username: email, next: "/auth/oauth/start?return_to=/login" }), { status: 200, headers });
+    // return_to=/drive: callback 後の /drive フルロードで発生していた resume DOM 破損 (#19) は
+    // #21 で修正済みのため、SPA 経路回避策 (return_to=/login) は解除する。
+    return new Response(JSON.stringify({ authenticated: true, username: email, next: "/auth/oauth/start?return_to=/drive" }), { status: 200, headers });
   } catch (err) {
     console.error("Kratos login error:", err);
     return Response.json({ error: "Authentication service unavailable" }, { status: 502 });
diff --git a/apps/booskiff-web/e2e/real/tests/auth.spec.ts b/apps/booskiff-web/e2e/real/tests/auth.spec.ts
index 1b5f5a1..b8f1a9f 100644
--- a/apps/booskiff-web/e2e/real/tests/auth.spec.ts
+++ b/apps/booskiff-web/e2e/real/tests/auth.spec.ts
@@ -16,10 +16,8 @@ async function enterCredentials(page: Page): Promise<void> {
   }).toPass({ timeout: 20_000 });
   // Real-mode login success hands off to /auth/oauth/start automatically (the
   // BFF `next` URL), so the Hydra consent screen arrives through the UI flow
-  // alone. return_to=/login is applied BFF-side: a direct full load of /drive
-  // after the OAuth callback corrupts the resumed DOM (issue #19), so landing
-  // on /login and letting the session check navigate client-side follows the
-  // healthy SPA path.
+  // alone. return_to=/drive: the OAuth callback lands on a full /drive load,
+  // whose resumed DOM stays intact since the issue #19 fix (#21).
   await expect(page.getByRole("button", { name: "Allow", exact: true })).toBeVisible({ timeout: 30_000 });
 }
 
@@ -89,12 +87,12 @@ test("real login grants a cookie session, drive access, and logout", async ({ pa
   const created = page.waitForResponse((response) => new URL(response.url()).pathname === "/api/folders" && response.request().method() === "POST");
   await page.getByTestId("folder-create-submit").click();
   expect((await created).ok()).toBe(true);
-  // Persistence is verified through the API: a full /drive reload re-triggers the
-  // resumed-DOM corruption noted above, so the browser-side reload assertion is
-  // intentionally left to the follow-up fix.
-  const folders = await page.request.get("/api/folders");
-  expect(folders.ok()).toBe(true);
-  expect(JSON.stringify(await folders.json())).toContain(folder);
+  // Persistence is verified through the UI after a full /drive reload: SSR +
+  // resumeMount must render the stored folder without the DOM corruption that
+  // issue #19 documented (fixed in #21).
+  await page.goto("/drive");
+  await expect(page.getByTestId("drive-page")).toBeVisible();
+  await expect(page.getByTestId("folder-list")).toContainText(folder);
 
   await page.getByTestId("logout-button").click();
   await expect(page).toHaveURL(/\/login$/);
diff --git a/apps/booskiff-web/e2e/tests/drive-resume.spec.ts b/apps/booskiff-web/e2e/tests/drive-resume.spec.ts
new file mode 100644
index 0000000..c4b9273
--- /dev/null
+++ b/apps/booskiff-web/e2e/tests/drive-resume.spec.ts
@@ -0,0 +1,45 @@
+import { expect, test } from "@playwright/test";
+import { folderRow, loginViaUi, runId } from "./helpers";
+
+// Regression for #19 / #21: an authenticated FULL page load of /drive (SSR +
+// resumeMount, then CheckSession -> LoadDrive -> *Loaded patches) must not
+// corrupt the client DOM. The observed corruption was duplicated folder
+// section elements (folder-create-submit / folder-list rendered twice),
+// children leaking between sections, and dead event handlers.
+test("authenticated /drive full reload keeps a single, working folder section", async ({
+  page,
+}) => {
+  await loginViaUi(page);
+
+  // Full page load: SSR HTML + resumeMount + session/drive data patches.
+  // Register response waits BEFORE the navigation so no patch is missed.
+  const filesLoaded = page.waitForResponse(
+    (response) =>
+      response.url().includes("/api/files") &&
+      response.request().method() === "GET",
+  );
+  const foldersLoaded = page.waitForResponse(
+    (response) =>
+      response.url().includes("/api/folders") &&
+      response.request().method() === "GET",
+  );
+  const billingLoaded = page.waitForResponse(
+    (response) => response.url().includes("/api/billing/status"),
+  );
+  await page.goto("/drive");
+  await filesLoaded;
+  await foldersLoaded;
+  await billingLoaded;
+  await expect(page.getByTestId("drive-page")).toBeVisible();
+
+  // Folder section elements must exist exactly once (no duplication).
+  await expect(page.getByTestId("folder-create-submit")).toHaveCount(1);
+  await expect(page.getByTestId("folder-list")).toHaveCount(1);
+  await expect(page.getByTestId("folder-name-input")).toHaveCount(1);
+
+  // Event handlers must survive resume: folder creation still works.
+  const name = `resume-${runId}`;
+  await page.getByTestId("folder-name-input").fill(name);
+  await page.getByTestId("folder-create-submit").click();
+  await expect(folderRow(page, name)).toBeVisible({ timeout: 15_000 });
+});
diff --git a/apps/booskiff-web/src/App/View/Drive.purs b/apps/booskiff-web/src/App/View/Drive.purs
index a3fb103..4d18e23 100644
--- a/apps/booskiff-web/src/App/View/Drive.purs
+++ b/apps/booskiff-web/src/App/View/Drive.purs
@@ -33,9 +33,17 @@ view model =
     , fileSection model
     ]
 
+-- | Invisible stand-in for "render nothing" slots. An empty text node never
+-- | survives HTML parsing, but Flame's hydration matches SSR DOM to virtual
+-- | children purely by index — a vanished placeholder shifts every following
+-- | sibling onto the wrong node and later patches then corrupt the DOM
+-- | (duplicated sections, leaked children, dead handlers; #19/#21).
+emptySlot :: Html Message
+emptySlot = HE.div [ HA.style { display: "none" } ] []
+
 errorBanner :: Maybe String -> Html Message
 errorBanner = case _ of
-  Nothing -> HE.text ""
+  Nothing -> emptySlot
   Just msg ->
     HE.div
       [ HA.class'
@@ -96,8 +104,8 @@ uploadSection model =
             ]
             [ HE.text "アップロード" ]
         ]
-    , maybe (HE.text "") progressView model.upload
-    , maybe (HE.text "") uploadErrorView (uploadErrorFor model)
+    , maybe emptySlot progressView model.upload
+    , maybe emptySlot uploadErrorView (uploadErrorFor model)
     ]
 
 uploadErrorFor :: Model -> Maybe String
@@ -166,7 +174,7 @@ folderSection model =
 
 allButton :: Maybe String -> Html Message
 allButton = case _ of
-  Nothing -> HE.text ""
+  Nothing -> emptySlot
   Just _ ->
     HE.button
       [ HA.class' ("text-sm " <> T.navLink)