@@ -297,12 +297,18 @@ describe.each(TOPOLOGIES)('%s kernel — a page saved as a second default record
 // is the page parse's: a non-record page's `isDefault: true`, the retired
 // `full-width` template and a region the template does not place are each
 // refused 422 `INVALID_METADATA` at save. A row ALREADY stored in one of those
-// shapes is read as it was (no conversion touches it and the read path does
-// not refuse it); saving it again is refused until it is fixed.
-const PLACEMENT_SHAPES: ReadonlyArray<[label: string, body: Record<string, unknown>, says: string]> = [
-    ['a home page with `isDefault: true`', { name: 'env_shape', label: 'Shape', type: 'home', isDefault: true, regions: [] }, '`isDefault: true` is refused'],
-    ['the retired `full-width` template', { name: 'env_shape', label: 'Shape', type: 'record', object: 'acme_task', template: 'full-width', regions: [{ name: 'main', components: [] }] }, "`template: 'full-width'` was removed"],
-    ['a `left_sidebar` region on `three-column`', { name: 'env_shape', label: 'Shape', type: 'home', template: 'three-column', regions: [{ name: 'left_sidebar', components: [] }, { name: 'main', components: [] }] }, 'Region `left_sidebar` is refused'],
+// shapes is read back through the stored-row conversion chain (the read path
+// never refuses it): the two shapes with a lossless rewrite come back
+// CONVERTED — the retired D2 entries `page-is-default-off-record-page-removed`
+// and `page-template-full-width-to-default` delete the flag and re-spell the
+// template — while the unplaced region, which has no lossless rewrite, is
+// served as stored. Saving the row as it was stored is refused until it is
+// fixed, whichever way it reads back. `served` is what the read answers for
+// the keys the shape varies.
+const PLACEMENT_SHAPES: ReadonlyArray<[label: string, body: Record<string, unknown>, says: string, served: Record<string, unknown>]> = [
+    ['a home page with `isDefault: true`', { name: 'env_shape', label: 'Shape', type: 'home', isDefault: true, regions: [] }, '`isDefault: true` is refused', { isDefault: undefined, regions: [] }],
+    ['the retired `full-width` template', { name: 'env_shape', label: 'Shape', type: 'record', object: 'acme_task', template: 'full-width', regions: [{ name: 'main', components: [] }] }, "`template: 'full-width'` was removed", { template: 'default', regions: [{ name: 'main', components: [] }] }],
+    ['a `left_sidebar` region on `three-column`', { name: 'env_shape', label: 'Shape', type: 'home', template: 'three-column', regions: [{ name: 'left_sidebar', components: [] }, { name: 'main', components: [] }] }, 'Region `left_sidebar` is refused', { template: 'three-column', regions: [{ name: 'left_sidebar', components: [] }, { name: 'main', components: [] }] }],
 ];
 
 describe.each(TOPOLOGIES)('%s kernel — the page parse at the save door, and rows stored before it (#23610)', (topology) => {
@@ -316,15 +322,14 @@ describe.each(TOPOLOGIES)('%s kernel — the page parse at the save door, and ro
         expect(storedPages()).toEqual([]);
     });
 
-    it.each(PLACEMENT_SHAPES)('%s, ALREADY stored: the read serves the row as stored, and saving it again is refused', async (_label, body) => {
+    it.each(PLACEMENT_SHAPES)('%s, ALREADY stored: the read serves the row through the stored-row conversion chain, and saving it as stored is refused', async (_label, body, _says, served) => {
         const { protocol, save, storeRow } = await boot(topology);
         await storeRow('env_shape', body);
         const read: any = await protocol.getMetaItem({ type: 'page', name: 'env_shape' });
         expect(read?.item?.name).toBe('env_shape');
-        for (const key of ['isDefault', 'template'] as const) {
-            if (key in body) expect(read.item[key]).toEqual(body[key]);
+        for (const [key, value] of Object.entries(served)) {
+            expect(read.item[key], key).toEqual(value);
         }
-        expect(read.item.regions).toEqual(body.regions);
         const again = await save('env_shape', body);
         expect(again.ok, 'the re-save was refused').toBe(false);
         expect((again as { error: any }).error?.status).toBe(422);
 
@@ -334,6 +334,28 @@ const JOIN: Readonly<Record<string, readonly Renderer[]>> = {
   ],
   // #23650: retired after 17.7.0, so the v18 train's major.
   'page-header-show-star-removed': [tombstone(PageHeaderProps, 'page:header', 'showStar')],
+  // #23904: the two data-at-rest halves of the #23610 page refusals, retired
+  // after 17.7.0; each prescription is the parse's own refusal at its key — the
+  // one sentence the registry door prints too — and names the release.
+  'page-is-default-off-record-page-removed': [
+    refusal(
+      "isDefault: true on a type 'home' page",
+      () => PageSchema.safeParse({ name: 'sales_home_page', label: 'Sales Home', type: 'home', isDefault: true, regions: [] }),
+      'isDefault',
+    ),
+    refusal(
+      'isDefault: true on a record page bound to no object',
+      () => PageSchema.safeParse({ name: 'draft_record', label: 'Draft', type: 'record', isDefault: true, regions: [] }),
+      'isDefault',
+    ),
+  ],
+  'page-template-full-width-to-default': [
+    refusal(
+      "page template 'full-width'",
+      () => PageSchema.safeParse({ name: 'lead_detail_page', label: 'Lead', type: 'record', object: 'crm_lead', template: 'full-width', regions: [{ name: 'main', components: [] }] }),
+      'template',
+    ),
+  ],
   // #23543 F3: a loose `config` key under a sibling-block node type, refused by
   // the flow parse; the node's block is complete, so the key is the only issue.
   'flow-node-wait-event-config-lift': [
 
@@ -89,19 +89,23 @@ export function defaultRecordPageObject(page: unknown): string | undefined {
  * without a parse.
  *
  * Reads a parsed page and an unparsed one alike, by the same declared keys
- * {@link defaultRecordPageObject} reads.
+ * {@link defaultRecordPageObject} reads. The sentence names the release that
+ * first refused the flag (`@objectstack/spec 18`): the retired D2 entry
+ * `page-is-default-off-record-page-removed` converts data at rest, and the
+ * removal-version pin holds every such prescription to the release its
+ * `retiredAfter` derives.
  */
 export function misplacedDefaultPageRefusal(page: unknown): string | undefined {
   if (!page || typeof page !== 'object' || Array.isArray(page)) return undefined;
   const p = page as Record<string, unknown>;
   if (p.isDefault !== true || defaultRecordPageObject(page) !== undefined) return undefined;
   const type = p.type === undefined ? PAGE_TYPE_DEFAULT : p.type;
   if (type === 'record') {
-    return '`isDefault: true` is refused on a record page bound to no `object`: it makes a record page the '
+    return '`isDefault: true` is refused on a record page bound to no `object` since @objectstack/spec 18: it makes a record page the '
       + 'default record page of the object it binds, the page that object\'s record view opens. Bind the '
       + 'page (`object: \'<object name>\'`), or delete `isDefault`.';
   }
-  return `\`isDefault: true\` is refused on a \`type: '${String(type)}'\` page: it marks the default record page `
+  return `\`isDefault: true\` is refused on a \`type: '${String(type)}'\` page since @objectstack/spec 18: it marks the default record page `
     + 'of an object, and nothing reads it on any other page. A page does not choose where an app opens — an '
     + 'app\'s landing page is its first navigation item (by `order`), so to land on this page put its entry '
     + 'first in the app\'s `navigation`; the root landing follows the app\'s own `isDefault`. Delete '