diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5bdae4fa6..cfecce59f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -76,8 +76,10 @@ an earlier fold computed from part of a day.
   when each type last arrived, by which trigger (including the new
   `manual` for Sync all) and when it last brought a new value
   (migration 0384).
-- **Documents layout.** Preview cards or a compact list, months stacked or
-  flowing, per account (migration 0388).
+- **Documents layout.** Preview cards or a compact list, months flowing
+  side by side (the default) or stacked, per account (migration 0388). Only
+  a field the person picked is stored, so an untouched one follows the
+  default.
 - **Measurement maintenance.** An admin card and
   `POST /api/admin/maintenance/measurements` run `VACUUM (ANALYZE)` and a
   `REINDEX INDEX CONCURRENTLY` per index, largest first.
diff --git a/docs/api/openapi.yaml b/docs/api/openapi.yaml
index 323f63544..24679b910 100644
--- a/docs/api/openapi.yaml
+++ b/docs/api/openapi.yaml
@@ -71374,7 +71374,7 @@ components:
             - stacked
             - flow
           description: '`stacked` gives every month its own block; `flow` runs the documents across the full width and wraps, with
-            month names inline. Default "stacked".'
+            month names inline. Default "flow"; an account that never chose keeps following the default.'
       required:
         - version
         - view
diff --git a/src/app/api/documents/inbound/layout/__tests__/route.test.ts b/src/app/api/documents/inbound/layout/__tests__/route.test.ts
index 8c267af61..41ca79b2b 100644
--- a/src/app/api/documents/inbound/layout/__tests__/route.test.ts
+++ b/src/app/api/documents/inbound/layout/__tests__/route.test.ts
@@ -89,9 +89,27 @@ describe("GET /api/documents/inbound/layout", () => {
     const res = await callGet();
     expect(res.status).toBe(200);
     expect((await res.json()).data).toEqual(DEFAULT_DOCUMENTS_LAYOUT);
+    expect(DEFAULT_DOCUMENTS_LAYOUT).toEqual({
+      version: 1,
+      view: "cards",
+      arrangement: "flow",
+    });
     expect(prisma.user.update).not.toHaveBeenCalled();
   });
 
+  it("keeps a saved stacked arrangement although the default is flow", async () => {
+    vi.mocked(prisma.user.findUnique).mockResolvedValue({
+      documentsLayoutJson: {
+        version: 1,
+        view: "cards",
+        arrangement: "stacked",
+      },
+    } as never);
+
+    const res = await callGet();
+    expect((await res.json()).data.arrangement).toBe("stacked");
+  });
+
   it("serves the stored choice, repairing an unknown value field by field", async () => {
     vi.mocked(prisma.user.findUnique).mockResolvedValue({
       documentsLayoutJson: { version: 1, view: "list", arrangement: "spiral" },
@@ -101,7 +119,7 @@ describe("GET /api/documents/inbound/layout", () => {
     expect((await res.json()).data).toEqual({
       version: 1,
       view: "list",
-      arrangement: "stacked",
+      arrangement: "flow",
     });
   });
 
@@ -146,6 +164,23 @@ describe("PUT /api/documents/inbound/layout", () => {
     });
   });
 
+  it("stores only the chosen field, so the untouched one keeps following the default", async () => {
+    vi.mocked(prisma.user.findUnique).mockResolvedValue({
+      documentsLayoutJson: null,
+    } as never);
+
+    const res = await put({ version: 1, view: "list" });
+    expect((await res.json()).data).toEqual({
+      version: 1,
+      view: "list",
+      arrangement: "flow",
+    });
+    expect(prisma.user.update).toHaveBeenCalledWith({
+      where: { id: "user-1" },
+      data: { documentsLayoutJson: { version: 1, view: "list" } },
+    });
+  });
+
   it("refuses an unknown value and an unknown key with 422 and writes nothing", async () => {
     const bad = await put({ version: 1, view: "carousel" });
     expect(bad.status).toBe(422);
diff --git a/src/app/api/documents/inbound/layout/route.ts b/src/app/api/documents/inbound/layout/route.ts
index 45d3e2b94..e81e5bca8 100644
--- a/src/app/api/documents/inbound/layout/route.ts
+++ b/src/app/api/documents/inbound/layout/route.ts
@@ -20,6 +20,7 @@ import {
   DOCUMENTS_LAYOUT_ARRANGEMENTS,
   DOCUMENTS_LAYOUT_VIEWS,
   resolveDocumentsLayout,
+  storedDocumentsLayoutChoices,
   type DocumentsLayout,
 } from "@/lib/documents/documents-layout";
 import { annotate } from "@/lib/logging/context";
@@ -35,12 +36,12 @@ const layoutPutSchema = z
   })
   .strict();
 
-async function readLayout(userId: string): Promise<DocumentsLayout> {
+async function readStoredLayout(userId: string): Promise<unknown> {
   const row = await prisma.user.findUnique({
     where: { id: userId },
     select: { documentsLayoutJson: true },
   });
-  return resolveDocumentsLayout(row?.documentsLayoutJson);
+  return row?.documentsLayoutJson;
 }
 
 export const GET = apiHandler(async () => {
@@ -51,7 +52,7 @@ export const GET = apiHandler(async () => {
   const gate = await requireModuleEnabled(user.id, "inboundDocuments");
   if (!gate.enabled) return gate.response;
 
-  const layout = await readLayout(user.id);
+  const layout = resolveDocumentsLayout(await readStoredLayout(user.id));
   annotate({
     action: { name: "documents.layout.read" },
     meta: { view: layout.view, arrangement: layout.arrangement },
@@ -78,17 +79,20 @@ export const PUT = apiHandler(async (request: Request) => {
   }
 
   // Preserve-when-absent: one stored read fills whichever field the body
-  // left out.
-  const existing = await readLayout(user.id);
-  const next: DocumentsLayout = {
-    version: 1,
-    view: parsed.data.view ?? existing.view,
-    arrangement: parsed.data.arrangement ?? existing.arrangement,
+  // left out. Only fields the user has chosen are written, so a field never
+  // picked keeps following the default (which can change between releases).
+  const choices = {
+    ...storedDocumentsLayoutChoices(await readStoredLayout(user.id)),
+    ...(parsed.data.view ? { view: parsed.data.view } : {}),
+    ...(parsed.data.arrangement
+      ? { arrangement: parsed.data.arrangement }
+      : {}),
   };
+  const next: DocumentsLayout = resolveDocumentsLayout(choices);
 
   await prisma.user.update({
     where: { id: user.id },
-    data: { documentsLayoutJson: toJson(next) },
+    data: { documentsLayoutJson: toJson({ version: 1, ...choices }) },
   });
 
   annotate({
diff --git a/src/components/documents/document-timeline.tsx b/src/components/documents/document-timeline.tsx
index d8eb507b7..a1b75597a 100644
--- a/src/components/documents/document-timeline.tsx
+++ b/src/components/documents/document-timeline.tsx
@@ -31,9 +31,10 @@ import { useVirtualizer } from "@tanstack/react-virtual";
 import { useTranslations } from "@/lib/i18n/context";
 import type { InboundDocumentDto } from "@/lib/validations/inbound-documents";
 import { UploadStateCard } from "./document-card";
-import type {
-  DocumentsLayoutArrangement,
-  DocumentsLayoutView,
+import {
+  DEFAULT_DOCUMENTS_LAYOUT,
+  type DocumentsLayoutArrangement,
+  type DocumentsLayoutView,
 } from "@/lib/documents/documents-layout";
 import {
   columnsForWidth,
@@ -65,8 +66,8 @@ export function DocumentTimeline({
   highlightId,
   onPrefetch,
   timezone,
-  view = "cards",
-  arrangement = "stacked",
+  view = DEFAULT_DOCUMENTS_LAYOUT.view,
+  arrangement = DEFAULT_DOCUMENTS_LAYOUT.arrangement,
 }: {
   /** Preview tiles or compact rows (the reader's vault presentation). */
   view?: DocumentsLayoutView;
diff --git a/src/lib/documents/documents-layout.ts b/src/lib/documents/documents-layout.ts
index dc796ecd9..fcef2266d 100644
--- a/src/lib/documents/documents-layout.ts
+++ b/src/lib/documents/documents-layout.ts
@@ -10,9 +10,10 @@
  *   and wrap, with each month's name riding inline as a small marker that does
  *   not break the run.
  *
- * Null / missing column = the defaults below (cards, stacked — the vault as it
- * has always looked). The GET endpoint never lazy-writes, so the column only
- * carries data once the user has changed one of the two. Mirrors
+ * Null / missing column = the defaults below (cards, flowing months). The GET
+ * endpoint never lazy-writes, and the PUT stores only the fields the user has
+ * actually chosen, so a default that changes later reaches every account that
+ * never picked that field, while a saved choice stays. Mirrors
  * `medication-list-layout.ts`: tolerant resolver on read, normaliser on write,
  * preserve-when-absent PUT (see the route).
  */
@@ -33,7 +34,7 @@ export interface DocumentsLayout {
 export const DEFAULT_DOCUMENTS_LAYOUT: DocumentsLayout = {
   version: 1,
   view: "cards",
-  arrangement: "stacked",
+  arrangement: "flow",
 };
 
 function isView(value: unknown): value is DocumentsLayoutView {
@@ -68,3 +69,22 @@ export function resolveDocumentsLayout(raw: unknown): DocumentsLayout {
       : DEFAULT_DOCUMENTS_LAYOUT.arrangement,
   };
 }
+
+/**
+ * The fields a stored blob explicitly carries, each validated. Unknown or
+ * malformed values drop out, so the default fills them on read. The PUT
+ * merges into this rather than into the resolved layout, which keeps an
+ * untouched field following the default instead of freezing today's value.
+ */
+export function storedDocumentsLayoutChoices(
+  raw: unknown,
+): Partial<Pick<DocumentsLayout, "view" | "arrangement">> {
+  if (raw === null || raw === undefined || typeof raw !== "object") return {};
+  const blob = raw as { view?: unknown; arrangement?: unknown };
+  return {
+    ...(isView(blob.view) ? { view: blob.view } : {}),
+    ...(isArrangement(blob.arrangement)
+      ? { arrangement: blob.arrangement }
+      : {}),
+  };
+}
diff --git a/src/lib/openapi/routes/documents.ts b/src/lib/openapi/routes/documents.ts
index ce08c12f3..419876ce4 100644
--- a/src/lib/openapi/routes/documents.ts
+++ b/src/lib/openapi/routes/documents.ts
@@ -62,7 +62,7 @@ const documentsLayoutSchema = z
     arrangement: z
       .enum(DOCUMENTS_LAYOUT_ARRANGEMENTS)
       .describe(
-        '`stacked` gives every month its own block; `flow` runs the documents across the full width and wraps, with month names inline. Default "stacked".',
+        '`stacked` gives every month its own block; `flow` runs the documents across the full width and wraps, with month names inline. Default "flow"; an account that never chose keeps following the default.',
       ),
   })
   .meta({