diff --git a/frontend/src/components/ChannelDiscovery.tsx b/frontend/src/components/ChannelDiscovery.tsx
index f5a49278..ef651069 100644
--- a/frontend/src/components/ChannelDiscovery.tsx
+++ b/frontend/src/components/ChannelDiscovery.tsx
@@ -2,6 +2,7 @@ import { useEffect } from "react";
 import { useTranslation } from "react-i18next";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { qk } from "../lib/queryKeys";
+import { invalidateSubscription } from "../lib/subscriptionCache";
 import { UserPlus } from "lucide-react";
 import { api, type DiscoveredChannel } from "../lib/api";
 import { accountKey, LS } from "../lib/storage";
@@ -58,9 +59,7 @@ export default function ChannelDiscovery({
     onSuccess: (_data, c) => {
       // The channel moves from "discovery" to "subscribed", and its videos will start
       // arriving — refresh both lists plus the per-user status.
-      qc.invalidateQueries({ queryKey: qk.discoveredChannels() });
-      qc.invalidateQueries({ queryKey: qk.channels() });
-      qc.invalidateQueries({ queryKey: qk.myStatus() });
+      invalidateSubscription(qc, c.id);
       const name = c.title ?? c.id;
       // Name the channel and ship a typed payload so the inbox can offer "open in the
       // Channel manager" / "open on YouTube" links — kept after reload, when live
diff --git a/frontend/src/components/ChannelPage.tsx b/frontend/src/components/ChannelPage.tsx
index 86a400a3..4e436f9f 100644
--- a/frontend/src/components/ChannelPage.tsx
+++ b/frontend/src/components/ChannelPage.tsx
@@ -4,6 +4,7 @@ import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { useLiveQuery } from "../lib/useLiveQuery";
 import { channelDetailPollMs, useBackfillFeedRefresh } from "../lib/channelDetailPoll";
 import { qk } from "../lib/queryKeys";
+import { invalidateSubscription } from "../lib/subscriptionCache";
 import { useNavigationActions } from "./navigationContext";
 import { PriorityStepper } from "./ui/PriorityStepper";
 import { useChannelPriority } from "../lib/useChannelPriority";
@@ -181,12 +182,7 @@ export default function ChannelPage({
   const subscribe = useMutation({
     mutationFn: () => api.subscribeChannel(channelId),
     onSuccess: () => {
-      qc.invalidateQueries({ queryKey: qk.channel(channelId) });
-      qc.invalidateQueries({ queryKey: qk.feed() });
-      qc.invalidateQueries({ queryKey: qk.channels() });
-      // Match ChannelDiscovery: the channel leaves discovery and the manager's stats move.
-      qc.invalidateQueries({ queryKey: qk.myStatus() });
-      qc.invalidateQueries({ queryKey: qk.discoveredChannels() });
+      invalidateSubscription(qc, channelId);
       notify({ level: "info", message: t("channel.subscribed", { name: ch?.title ?? "" }) });
     },
     // A 403 (missing write scope) otherwise fails silently on the channel page (no wizard handle
@@ -195,11 +191,7 @@ export default function ChannelPage({
   });
   const unsubscribe = useMutation({
     mutationFn: () => api.unsubscribeChannel(channelId),
-    onSuccess: () => {
-      qc.invalidateQueries({ queryKey: qk.channel(channelId) });
-      qc.invalidateQueries({ queryKey: qk.feed() });
-      qc.invalidateQueries({ queryKey: qk.channels() });
-    },
+    onSuccess: () => invalidateSubscription(qc, channelId),
     onError: (err) => notifyYouTubeActionError(err, t("channels.notify.unsubscribeFailed")),
   });
   // "Get full history": the catalog only holds the recent-backfill/RSS subset of a channel's
diff --git a/frontend/src/components/useChannelActions.tsx b/frontend/src/components/useChannelActions.tsx
index 695c5349..0c123d61 100644
--- a/frontend/src/components/useChannelActions.tsx
+++ b/frontend/src/components/useChannelActions.tsx
@@ -2,6 +2,7 @@ import { useMutation, useQueryClient } from "@tanstack/react-query";
 import { useTranslation } from "react-i18next";
 import { ArrowUpDown, EyeOff, ExternalLink, History, Tags, Tv, UserMinus } from "lucide-react";
 import { qk } from "../lib/queryKeys";
+import { invalidateSubscription } from "../lib/subscriptionCache";
 import { api, type ManagedChannel, type Tag } from "../lib/api";
 import { priorityChoices } from "../lib/channelOrder";
 import { channelYouTubeUrl } from "../lib/format";
@@ -79,8 +80,7 @@ export function useChannelActions({
   const unsubscribe = useMutation({
     mutationFn: (c: ManagedChannel) => api.unsubscribeChannel(c.id),
     onSuccess: (_d, c) => {
-      qc.invalidateQueries({ queryKey: qk.channels() });
-      qc.invalidateQueries({ queryKey: qk.myStatus() });
+      invalidateSubscription(qc, c.id);
       notify({ level: "success", message: t("channels.notify.unsubscribed", { name: nameOf(c) }) });
     },
     onError: (e) =>
diff --git a/frontend/src/lib/subscriptionCache.test.ts b/frontend/src/lib/subscriptionCache.test.ts
new file mode 100644
index 00000000..90fd873f
--- /dev/null
+++ b/frontend/src/lib/subscriptionCache.test.ts
@@ -0,0 +1,38 @@
+import { readdirSync, readFileSync } from "node:fs";
+import { QueryClient } from "@tanstack/react-query";
+import { describe, expect, it, vi } from "vitest";
+
+import { qk } from "./queryKeys";
+import { invalidateSubscription } from "./subscriptionCache";
+
+// E28 review L8: a subscription change touches the same reads wherever it is made, and each site kept
+// its own list — the channel menu's unsubscribe left the feed showing the channel's videos, the
+// channel page's left the status counts stale. One set, one function, every site on it.
+describe("a subscription change", () => {
+  it("refreshes the channel, the lists, the counts and the feed", () => {
+    const qc = new QueryClient();
+    const spy = vi.spyOn(qc, "invalidateQueries");
+    invalidateSubscription(qc, "UC1");
+    expect(spy.mock.calls.map(([f]) => f?.queryKey)).toEqual([
+      qk.channel("UC1"),
+      qk.channels(),
+      qk.myStatus(),
+      qk.feed(),
+      qk.feedSummary(),
+      qk.discoveredChannels(),
+    ]);
+  });
+
+  it("is refreshed through that one function wherever it is made", () => {
+    const root = new URL("../components/", import.meta.url);
+    const sites = readdirSync(root)
+      .filter((f) => f.endsWith(".tsx") && !f.includes(".test."))
+      .map((f) => [f, readFileSync(new URL(f, root), "utf8")] as const)
+      .filter(([, src]) => /api\.(un)?subscribeChannel\(/.test(src));
+    expect(sites.length).toBeGreaterThanOrEqual(3);
+    for (const [f, src] of sites) {
+      const calls = src.match(/api\.(un)?subscribeChannel\(/g)!.length;
+      expect(src.match(/invalidateSubscription\(/g)?.length ?? 0, f).toBe(calls);
+    }
+  });
+});
diff --git a/frontend/src/lib/subscriptionCache.ts b/frontend/src/lib/subscriptionCache.ts
new file mode 100644
index 00000000..aa1cdb85
--- /dev/null
+++ b/frontend/src/lib/subscriptionCache.ts
@@ -0,0 +1,19 @@
+import type { QueryClient } from "@tanstack/react-query";
+
+import { qk } from "./queryKeys";
+
+/** Everything a subscribe or an unsubscribe changes: the channel itself, the manager's list and its
+ *  counts, the feed and its facets (the channel's videos come or go), and discovery (a subscribed
+ *  channel leaves it). ONE set for every site that makes the change (E28 review L8): each used to keep
+ *  its own list, and each list missed something. */
+export function invalidateSubscription(qc: QueryClient, channelId: string): void {
+  for (const queryKey of [
+    qk.channel(channelId),
+    qk.channels(),
+    qk.myStatus(),
+    qk.feed(),
+    qk.feedSummary(),
+    qk.discoveredChannels(),
+  ])
+    void qc.invalidateQueries({ queryKey });
+}