diff --git a/Yattee/Data/DataManager+WatchHistory.swift b/Yattee/Data/DataManager+WatchHistory.swift
index 05659c3c..cf7633e8 100644
--- a/Yattee/Data/DataManager+WatchHistory.swift
+++ b/Yattee/Data/DataManager+WatchHistory.swift
@@ -136,7 +136,9 @@ extension DataManager {
     /// Returns a dictionary of video ID to WatchEntry for efficient bulk lookup.
     func watchEntriesMap() -> [String: WatchEntry] {
         let entries = watchHistory(limit: 10000)
-        return Dictionary(uniqueKeysWithValues: entries.map { ($0.videoID, $0) })
+        // The same video ID can be recorded under several source scopes; the
+        // history is most recent first, so the first entry is the one to keep.
+        return Dictionary(entries.map { ($0.videoID, $0) }, uniquingKeysWith: { first, _ in first })
     }
 
     /// Gets the total count of watch history entries.
diff --git a/Yattee/Views/Home/HomeView.swift b/Yattee/Views/Home/HomeView.swift
index cf089b33..3614cc0a 100644
--- a/Yattee/Views/Home/HomeView.swift
+++ b/Yattee/Views/Home/HomeView.swift
@@ -1990,9 +1990,10 @@ struct HomeView: View {
         }
 
         let known: [String: Video] = Dictionary(
-            uniqueKeysWithValues: ids.compactMap { id in
+            ids.compactMap { id in
                 dataManager?.watchEntry(for: id).map { (id, $0.toVideo()) }
-            }
+            },
+            uniquingKeysWith: { first, _ in first }
         )
 
         return await withTaskGroup(of: (Int, Video).self) { group in
diff --git a/Yattee/Views/Subscriptions/ManageChannelsView.swift b/Yattee/Views/Subscriptions/ManageChannelsView.swift
index a7941119..5bdde826 100644
--- a/Yattee/Views/Subscriptions/ManageChannelsView.swift
+++ b/Yattee/Views/Subscriptions/ManageChannelsView.swift
@@ -263,8 +263,10 @@ struct ManageChannelsView: View {
             if let syncChannels = subscriptionService?.fetchSubscriptionsSync() {
                 channels = syncChannels
             }
+            // A channel can be subscribed under several account scopes.
             subscriptionMetadata = Dictionary(
-                uniqueKeysWithValues: (dataManager?.subscriptions() ?? []).map { ($0.channelID, $0) }
+                (dataManager?.subscriptions() ?? []).map { ($0.channelID, $0) },
+                uniquingKeysWith: { first, _ in first }
             )
         }
         .task {