Stabilize schedule e2e date fixtures

src/features/online-board/components/DayTabs/DayTabs.test.tsx

@@ -155,6 +155,22 @@ describe("DayTabs", () => {
     expect(screen.getByTestId("day-select")).toBeTruthy();
   });
 
+  it("deduplicates available dates before rendering the mobile select", () => {
+    render(
+      <DayTabs
+        selectedDate="20260416"
+        availableDates={["20260416", "20260416", "20260417"]}
+        daysBefore={1}
+        daysAfter={2}
+        locale="en"
+        onNavigate={() => {}}
+      />,
+    );
+
+    const options = screen.getByTestId("day-select").querySelectorAll("option");
+    expect(options).toHaveLength(2);
+  });
+
   // ── TZ §4.1.13.1 compliance tests ──────────────────────────────────────
 
   it("4.1.13.1: active range today-1 to today+14 yields 16 total dates", () => {

src/features/online-board/components/DayTabs/DayTabs.tsx

@@ -68,8 +68,15 @@ export const DayTabs: FC<DayTabsProps> = ({
   // the route has no day data). Treat every date as tappable in that
   // case — matches Angular where the tabs stay enabled until we *know*
   // the upstream reports no flights for a given day.
-  const availableSet = useMemo(() => new Set(availableDates), [availableDates]);
-  const disableByAvailability = availableDates.length > 0;
+  const uniqueAvailableDates = useMemo(
+    () => Array.from(new Set(availableDates)),
+    [availableDates],
+  );
+  const availableSet = useMemo(
+    () => new Set(uniqueAvailableDates),
+    [uniqueAvailableDates],
+  );
+  const disableByAvailability = uniqueAvailableDates.length > 0;
 
   const visibleDates = allDates.slice(
     currentPage * PAGE_SIZE,
@@ -150,7 +157,7 @@ export const DayTabs: FC<DayTabsProps> = ({
       </div>
       <DaySelect
         selectedDate={selectedDate}
-        availableDates={availableDates}
+        availableDates={uniqueAvailableDates}
         locale={locale}
         onNavigate={onNavigate}
         {...(mobileCaptionKey ? { captionKey: mobileCaptionKey } : {})}