diff --git a/packages/shared/src/repository.test.ts b/packages/shared/src/repository.test.ts
new file mode 100644
index 0000000000..b964b9ae57
--- /dev/null
+++ b/packages/shared/src/repository.test.ts
@@ -0,0 +1,32 @@
+import { describe, expect, it } from "vitest";
+import { getTaskRepository, parseRepository } from "./repository";
+
+describe("getTaskRepository", () => {
+  it.each([
+    { name: "undefined task", task: undefined, expected: null },
+    { name: "null task", task: null, expected: null },
+    { name: "missing repository", task: {}, expected: null },
+    { name: "null repository", task: { repository: null }, expected: null },
+    {
+      name: "populated repository",
+      task: { repository: "posthog/code" },
+      expected: "posthog/code",
+    },
+  ])("returns $expected for $name", ({ task, expected }) => {
+    expect(getTaskRepository(task)).toBe(expected);
+  });
+});
+
+describe("parseRepository", () => {
+  it("splits an org/repo string", () => {
+    expect(parseRepository("posthog/code")).toEqual({
+      organization: "posthog",
+      repoName: "code",
+    });
+  });
+
+  it("returns null for malformed input", () => {
+    expect(parseRepository("code")).toBeNull();
+    expect(parseRepository("a/b/c")).toBeNull();
+  });
+});
diff --git a/packages/shared/src/repository.ts b/packages/shared/src/repository.ts
index 2902588698..c7b70b5d5f 100644
--- a/packages/shared/src/repository.ts
+++ b/packages/shared/src/repository.ts
@@ -10,8 +10,8 @@ export const parseRepository = (
   return { organization: result[0], repoName: result[1] };
 };
 
-export function getTaskRepository(task: {
-  repository?: string | null;
-}): string | null {
-  return task.repository ?? null;
+export function getTaskRepository(
+  task: { repository?: string | null } | null | undefined,
+): string | null {
+  return task?.repository ?? null;
 }
diff --git a/packages/ui/src/features/task-detail/hooks/useRefreshedTask.test.tsx b/packages/ui/src/features/task-detail/hooks/useRefreshedTask.test.tsx
index 9d11d1c35a..166e7f50a5 100644
--- a/packages/ui/src/features/task-detail/hooks/useRefreshedTask.test.tsx
+++ b/packages/ui/src/features/task-detail/hooks/useRefreshedTask.test.tsx
@@ -5,12 +5,24 @@ import type { PropsWithChildren } from "react";
 import { beforeEach, describe, expect, it, vi } from "vitest";
 import { useRefreshedTask } from "./useRefreshedTask";
 
-const mocks = vi.hoisted(() => ({ getTask: vi.fn() }));
+const mocks = vi.hoisted(() => ({
+  getTask: vi.fn(),
+  useQuery: vi.fn(),
+  actualUseQuery: undefined as unknown,
+}));
 
 vi.mock("@posthog/ui/features/auth/authClientImperative", () => ({
   getAuthenticatedClient: vi.fn(async () => ({ getTask: mocks.getTask })),
 }));
 
+vi.mock("@tanstack/react-query", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("@tanstack/react-query")>();
+  // Keep a handle on the real useQuery so beforeEach can restore delegation
+  // after a test overrides the mock's return value.
+  mocks.actualUseQuery = actual.useQuery;
+  return { ...actual, useQuery: mocks.useQuery };
+});
+
 function task(runId: string, status: "failed" | "in_progress"): Task {
   return {
     id: "task-123",
@@ -30,6 +42,27 @@ function task(runId: string, status: "failed" | "in_progress"): Task {
 describe("useRefreshedTask", () => {
   beforeEach(() => {
     mocks.getTask.mockReset();
+    mocks.useQuery.mockReset();
+    // Delegate to the real useQuery by default; a test can override the return
+    // value to simulate a specific cache state.
+    mocks.useQuery.mockImplementation(
+      mocks.actualUseQuery as typeof import("@tanstack/react-query").useQuery,
+    );
+  });
+
+  it("falls back to initialTask when the query yields undefined data", () => {
+    // A separate observer subscribing to the same query key without initialData
+    // can create the cache entry first while the fetch is in flight, so React
+    // Query hands this hook `data: undefined` despite the initialData option.
+    // The hook must never surface undefined (it flows into getTaskRepository).
+    mocks.useQuery.mockReturnValue({ data: undefined });
+    const initialTask = task("run-parent", "in_progress");
+
+    const { result } = renderHook(() =>
+      useRefreshedTask("task-123", initialTask),
+    );
+
+    expect(result.current).toBe(initialTask);
   });
 
   it("replaces a cached failed run with the authoritative resumed run", async () => {
diff --git a/packages/ui/src/features/task-detail/hooks/useRefreshedTask.ts b/packages/ui/src/features/task-detail/hooks/useRefreshedTask.ts
index e2f6be477d..f8ddc9a4b5 100644
--- a/packages/ui/src/features/task-detail/hooks/useRefreshedTask.ts
+++ b/packages/ui/src/features/task-detail/hooks/useRefreshedTask.ts
@@ -9,5 +9,8 @@ export function useRefreshedTask(taskId: string, initialTask: Task): Task {
     refetchOnMount: "always",
   });
 
-  return data;
+  // Guard against `data` being undefined: another observer subscribing to the
+  // same query key without `initialData` can create the cache entry first while
+  // the fetch is in flight, causing React Query to drop this hook's initialData.
+  return data ?? initialTask;
 }