diff --git a/examples/app-showcase/src/data/objects/expense-report.object.ts b/examples/app-showcase/src/data/objects/expense-report.object.ts
index e958c93273..10eb212be5 100644
--- a/examples/app-showcase/src/data/objects/expense-report.object.ts
+++ b/examples/app-showcase/src/data/objects/expense-report.object.ts
@@ -164,6 +164,22 @@ export const ExpenseLine = ObjectSchema.create({
         { label: 'Rejected', value: 'rejected', color: '#EF4444' },
       ],
     }),
+    /**
+     * The exact instant on the receipt — a meal at 19:45, a cab at 07:12.
+     *
+     * Deliberately a `datetime` sitting NEXT TO the `date` below: the two are
+     * the inline grid's temporal-type fixture (objectui#3569). A renderer that
+     * folds `datetime` onto the `date` control does not merely hide the clock —
+     * `<input type="date">` emits a bare `YYYY-MM-DD`, so a user correcting the
+     * DAY writes the time out of the record. Nothing in showcase could catch
+     * that before, because no inline-grid child carried a datetime at all.
+     *
+     * Keep both columns: the pair is what makes the distinction observable.
+     * With seven editable fields the grid's six-column default budget parks one
+     * of them in the column chooser (`incurred_on`, by declaration order) — that
+     * is the intended "personalize columns" behaviour, not a dropped field.
+     */
+    incurred_at: Field.datetime({ label: 'Incurred At' }),
     incurred_on: Field.date({ label: 'Incurred On' }),
   },
 });
diff --git a/examples/app-showcase/src/data/seed/index.ts b/examples/app-showcase/src/data/seed/index.ts
index 91fdca7a5c..0b395113b0 100644
--- a/examples/app-showcase/src/data/seed/index.ts
+++ b/examples/app-showcase/src/data/seed/index.ts
@@ -388,27 +388,36 @@ const expenseReports = defineSeed(ExpenseReport, {
   ],
 });
 
+/**
+ * Every line carries BOTH temporal shapes — `incurred_on` (calendar day) and
+ * `incurred_at` (instant) — and every `incurred_at` has a NON-ZERO time
+ * component on purpose (objectui#3569). A wall clock of `00:00` would make the
+ * defect invisible: a renderer that drops the time would look identical to one
+ * that keeps it. `daysAgo(n)` is a calendar-day function resolving to UTC
+ * midnight, so the clock is added with the sub-day idiom the formula stdlib
+ * documents for exactly this — `<timestamp> + duration("Nh…")`.
+ */
 const expenseLines = defineSeed(ExpenseLine, {
   mode: 'upsert',
   externalId: 'merchant',
   records: [
     // EXP-2001 → total 1500.50 · approved 960 · reimbursable 512 · rejected 0 · over$500 2
-    { merchant: 'United Airlines', expense_report: 'EXP-2001', category: 'travel', amount: 620, billable: false, status: 'approved', incurred_on: cel`daysAgo(9)` },
-    { merchant: 'Marriott Downtown', expense_report: 'EXP-2001', category: 'lodging', amount: 340, billable: false, status: 'approved', incurred_on: cel`daysAgo(8)` },
-    { merchant: 'Chipotle', expense_report: 'EXP-2001', category: 'meals', amount: 28.5, billable: false, status: 'submitted', incurred_on: cel`daysAgo(8)` },
-    { merchant: 'AWS', expense_report: 'EXP-2001', category: 'software', amount: 512, billable: true, status: 'submitted', incurred_on: cel`daysAgo(7)` },
+    { merchant: 'United Airlines', expense_report: 'EXP-2001', category: 'travel', amount: 620, billable: false, status: 'approved', incurred_on: cel`daysAgo(9)`, incurred_at: cel`daysAgo(9) + duration("6h20m")` },
+    { merchant: 'Marriott Downtown', expense_report: 'EXP-2001', category: 'lodging', amount: 340, billable: false, status: 'approved', incurred_on: cel`daysAgo(8)`, incurred_at: cel`daysAgo(8) + duration("15h05m")` },
+    { merchant: 'Chipotle', expense_report: 'EXP-2001', category: 'meals', amount: 28.5, billable: false, status: 'submitted', incurred_on: cel`daysAgo(8)`, incurred_at: cel`daysAgo(8) + duration("19h45m")` },
+    { merchant: 'AWS', expense_report: 'EXP-2001', category: 'software', amount: 512, billable: true, status: 'submitted', incurred_on: cel`daysAgo(7)`, incurred_at: cel`daysAgo(7) + duration("2h10m")` },
     // EXP-2002 → total 917 · approved 825 · reimbursable 825 · rejected 1 · over$500 1
-    { merchant: 'Delta Air Lines', expense_report: 'EXP-2002', category: 'travel', amount: 780, billable: true, status: 'approved', incurred_on: cel`daysAgo(15)` },
-    { merchant: 'Uber', expense_report: 'EXP-2002', category: 'travel', amount: 45, billable: true, status: 'approved', incurred_on: cel`daysAgo(14)` },
-    { merchant: 'Staples', expense_report: 'EXP-2002', category: 'supplies', amount: 92, billable: false, status: 'rejected', incurred_on: cel`daysAgo(14)` },
+    { merchant: 'Delta Air Lines', expense_report: 'EXP-2002', category: 'travel', amount: 780, billable: true, status: 'approved', incurred_on: cel`daysAgo(15)`, incurred_at: cel`daysAgo(15) + duration("7h35m")` },
+    { merchant: 'Uber', expense_report: 'EXP-2002', category: 'travel', amount: 45, billable: true, status: 'approved', incurred_on: cel`daysAgo(14)`, incurred_at: cel`daysAgo(14) + duration("21h50m")` },
+    { merchant: 'Staples', expense_report: 'EXP-2002', category: 'supplies', amount: 92, billable: false, status: 'rejected', incurred_on: cel`daysAgo(14)`, incurred_at: cel`daysAgo(14) + duration("11h15m")` },
     // EXP-2003 (draft) → total 225.75 · approved 0 · reimbursable 0 · rejected 0 · over$500 0
-    { merchant: 'Hilton Garden Inn', expense_report: 'EXP-2003', category: 'lodging', amount: 210, billable: false, status: 'submitted', incurred_on: cel`daysAgo(3)` },
-    { merchant: 'Starbucks', expense_report: 'EXP-2003', category: 'meals', amount: 15.75, billable: false, status: 'submitted', incurred_on: cel`daysAgo(2)` },
+    { merchant: 'Hilton Garden Inn', expense_report: 'EXP-2003', category: 'lodging', amount: 210, billable: false, status: 'submitted', incurred_on: cel`daysAgo(3)`, incurred_at: cel`daysAgo(3) + duration("14h30m")` },
+    { merchant: 'Starbucks', expense_report: 'EXP-2003', category: 'meals', amount: 15.75, billable: false, status: 'submitted', incurred_on: cel`daysAgo(2)`, incurred_at: cel`daysAgo(2) + duration("8h05m")` },
     // EXP-DEMO → total 8900 (≥ $5000, trips the committee-quorum threshold)
-    { merchant: 'Dreamforce Conference', expense_report: 'EXP-DEMO', category: 'other', amount: 3200, billable: true, status: 'submitted', incurred_on: cel`daysAgo(4)` },
-    { merchant: 'Lufthansa', expense_report: 'EXP-DEMO', category: 'travel', amount: 2400, billable: true, status: 'submitted', incurred_on: cel`daysAgo(4)` },
-    { merchant: 'Grand Hyatt', expense_report: 'EXP-DEMO', category: 'lodging', amount: 1800, billable: true, status: 'submitted', incurred_on: cel`daysAgo(3)` },
-    { merchant: 'Apple Store', expense_report: 'EXP-DEMO', category: 'software', amount: 1500, billable: true, status: 'submitted', incurred_on: cel`daysAgo(3)` },
+    { merchant: 'Dreamforce Conference', expense_report: 'EXP-DEMO', category: 'other', amount: 3200, billable: true, status: 'submitted', incurred_on: cel`daysAgo(4)`, incurred_at: cel`daysAgo(4) + duration("9h40m")` },
+    { merchant: 'Lufthansa', expense_report: 'EXP-DEMO', category: 'travel', amount: 2400, billable: true, status: 'submitted', incurred_on: cel`daysAgo(4)`, incurred_at: cel`daysAgo(4) + duration("5h25m")` },
+    { merchant: 'Grand Hyatt', expense_report: 'EXP-DEMO', category: 'lodging', amount: 1800, billable: true, status: 'submitted', incurred_on: cel`daysAgo(3)`, incurred_at: cel`daysAgo(3) + duration("17h55m")` },
+    { merchant: 'Apple Store', expense_report: 'EXP-DEMO', category: 'software', amount: 1500, billable: true, status: 'submitted', incurred_on: cel`daysAgo(3)`, incurred_at: cel`daysAgo(3) + duration("13h40m")` },
   ],
 });
 
diff --git a/examples/app-showcase/src/system/translations/index.ts b/examples/app-showcase/src/system/translations/index.ts
index fac1cd9cc8..284ea770c2 100644
--- a/examples/app-showcase/src/system/translations/index.ts
+++ b/examples/app-showcase/src/system/translations/index.ts
@@ -105,6 +105,22 @@ export const ShowcaseTranslationBundle = {
           total: { label: 'Total' },
         },
       },
+      // Translated at birth, like `globalActions` below and for the same
+      // reason: `incurred_at` is a NEW declared label (objectui#3569's inline-
+      // grid datetime fixture), and check-i18n-coverage freezes this example at
+      // its current untranslated count — a new label that skips zh-CN widens
+      // the debt and fails the ratchet.
+      //
+      // DELIBERATELY only this one field. The rest of the expense family
+      // (object labels, `incurred_on`, `merchant`, …) predates the ratchet and
+      // is part of the frozen baseline; translating it here too would push the
+      // count BELOW the baseline, which the same gate rejects as an
+      // un-ratcheted improvement. Paying that debt down is its own change.
+      showcase_expense_line: {
+        fields: {
+          incurred_at: { label: 'Incurred At' },
+        },
+      },
       showcase_preference: {
         label: 'Setting',
         pluralLabel: 'Settings',
@@ -372,6 +388,13 @@ export const ShowcaseTranslationBundle = {
           total: { label: '合计' },
         },
       },
+      // See the `en` side for why this entry translates exactly ONE field and
+      // no more (check-i18n-coverage is a two-sided ratchet).
+      showcase_expense_line: {
+        fields: {
+          incurred_at: { label: '发生时间' },
+        },
+      },
       showcase_preference: {
         label: '设置',
         pluralLabel: '设置',