diff --git a/packages/fields/src/widgets/GridField.test.tsx b/packages/fields/src/widgets/GridField.test.tsx
index 107ad5fff2..a5f8c44755 100644
--- a/packages/fields/src/widgets/GridField.test.tsx
+++ b/packages/fields/src/widgets/GridField.test.tsx
@@ -113,6 +113,62 @@ describe('GridField / LineItemsField — editable line items', () => {
     expect(onChange).toHaveBeenCalledWith([{ description: 'Taxi', amount: 42.5 }]);
   });
 
+  /**
+   * objectui#3566 — the sub-grid face of #3127. `<input type="date">` accepts
+   * exactly `YYYY-MM-DD` and rejects every other shape SILENTLY: the attribute
+   * still lands in the DOM, so the value looks present in the markup, while
+   * `.value` reads back `''` and the cell paints its empty placeholder. Since
+   * the API hands back `2026-06-17T00:00:00.000Z` for a `date` field, every
+   * date cell in an inline child grid rendered blank on a row that has a value.
+   * Asserting `.value` (never `getAttribute('value')`) is the only way to see
+   * this bug at all.
+   */
+  describe('date columns echo the stored value (#3566)', () => {
+    const dateField = {
+      columns: [
+        { field: 'description', label: 'Description', type: 'text' as const },
+        { field: 'incurred_on', label: 'Incurred On', type: 'date' as const },
+      ],
+    } as any;
+
+    // Both spellings the API may hand back for a `date` field. The bare form
+    // must survive VERBATIM — re-parsing it as UTC midnight and reading local
+    // calendar components back out would move it to the 16th anywhere west of
+    // Greenwich, which is the off-by-one this fix must not introduce.
+    it.each(['2026-06-17', '2026-06-17T00:00:00.000Z'])(
+      'shows the stored calendar day for %s instead of an empty cell',
+      (stored) => {
+        render(
+          <GridField value={[{ description: 'Taxi', incurred_on: stored }]} onChange={() => {}} field={dateField} />,
+        );
+        const cell = screen.getAllByLabelText('Incurred On')[0] as HTMLInputElement;
+        expect(cell.type).toBe('date');
+        expect(cell.value).toBe('2026-06-17');
+      },
+    );
+
+    it('leaves an empty date cell empty', () => {
+      render(<GridField value={[{ description: 'Taxi', incurred_on: null }]} onChange={() => {}} field={dateField} />);
+      expect((screen.getAllByLabelText('Incurred On')[0] as HTMLInputElement).value).toBe('');
+    });
+
+    it('writes back the control\'s own YYYY-MM-DD, unchanged by the read fix', () => {
+      // No paired conversion on the write side: `onChange` hands over exactly
+      // what `<input type="date">` produces, matching DateField's contract. A
+      // conversion here would put read and write on different bases.
+      const onChange = vi.fn();
+      render(
+        <GridField
+          value={[{ description: 'Taxi', incurred_on: '2026-06-17T00:00:00.000Z' }]}
+          onChange={onChange}
+          field={dateField}
+        />,
+      );
+      fireEvent.change(screen.getAllByLabelText('Incurred On')[0], { target: { value: '2026-06-18' } });
+      expect(onChange).toHaveBeenCalledWith([{ description: 'Taxi', incurred_on: '2026-06-18' }]);
+    });
+  });
+
   describe('trailing ghost row (start-with-one + auto-append)', () => {
     it('renders a trailing empty row so an empty grid still has one input line', () => {
       render(<GridField value={[]} onChange={() => {}} field={field} />);
diff --git a/packages/fields/src/widgets/GridField.tsx b/packages/fields/src/widgets/GridField.tsx
index 77c34d9411..453d32bbe2 100644
--- a/packages/fields/src/widgets/GridField.tsx
+++ b/packages/fields/src/widgets/GridField.tsx
@@ -19,6 +19,7 @@ import { Plus, Trash2, SlidersHorizontal, Maximize2, Copy, GripVertical } from '
 import { resolveFieldRuleState } from '@object-ui/core';
 import { LookupField } from './LookupField';
 import { FileCell } from './FileField';
+import { toDateInputValue } from './nativeDateValue';
 
 /**
  * GridField / LineItemsField — editable child-grid ("line items") widget.
@@ -760,7 +761,13 @@ export function GridField({
           type={c.type === 'date' ? 'date' : isNumeric(c.type) ? 'number' : 'text'}
           step={isNumeric(c.type) ? c.step ?? 'any' : undefined}
           aria-label={c.label || c.field}
-          value={val != null ? String(val) : ''}
+          // A `date` cell holding the API's ISO shape (`2026-06-17T00:00:00.000Z`)
+          // is SILENTLY rejected by `<input type="date">` — the attribute lands in
+          // the DOM but `input.value` reads back `''` and the cell paints empty
+          // (objectui#3566, the sub-grid face of #3127). The write-back shape is
+          // unchanged: the control's own plain `YYYY-MM-DD`, so no paired
+          // conversion is needed on the `onChange` side.
+          value={c.type === 'date' ? toDateInputValue(val) : val != null ? String(val) : ''}
           onChange={(e) => setCell(rowIdx, c, e.target.value)}
           disabled={locked}
         />