diff --git a/app/services/notify_service.rb b/app/services/notify_service.rb
index e56562c0a..1f01c2d48 100644
--- a/app/services/notify_service.rb
+++ b/app/services/notify_service.rb
@@ -147,6 +147,9 @@ class NotifyService < BaseService
     end
 
     def statuses_that_mention_sender
+      # This queries private mentions from the recipient to the sender up in the thread.
+      # This allows up to 100 messages that do not match in the thread, allowing conversations
+      # involving multiple people.
       Status.count_by_sql([<<-SQL.squish, id: @notification.target_status.in_reply_to_id, recipient_id: @recipient.id, sender_id: @sender.id, depth_limit: 100])
         WITH RECURSIVE ancestors(id, in_reply_to_id, mention_id, path, depth) AS (
             SELECT s.id, s.in_reply_to_id, m.id, ARRAY[s.id], 0
@@ -154,16 +157,17 @@ class NotifyService < BaseService
             LEFT JOIN mentions m ON m.silent = FALSE AND m.account_id = :sender_id AND m.status_id = s.id
             WHERE s.id = :id
           UNION ALL
-            SELECT s.id, s.in_reply_to_id, m.id, st.path || s.id, st.depth + 1
-            FROM ancestors st
-            JOIN statuses s ON s.id = st.in_reply_to_id
-            LEFT JOIN mentions m ON m.silent = FALSE AND m.account_id = :sender_id AND m.status_id = s.id
-            WHERE st.mention_id IS NULL AND NOT s.id = ANY(path) AND st.depth < :depth_limit
+            SELECT s.id, s.in_reply_to_id, m.id, ancestors.path || s.id, ancestors.depth + 1
+            FROM ancestors
+            JOIN statuses s ON s.id = ancestors.in_reply_to_id
+            /* early exit if we already have a mention matching our requirements */
+            LEFT JOIN mentions m ON m.silent = FALSE AND m.account_id = :sender_id AND m.status_id = s.id AND s.account_id = :recipient_id
+            WHERE ancestors.mention_id IS NULL AND NOT s.id = ANY(path) AND ancestors.depth < :depth_limit
         )
         SELECT COUNT(*)
-        FROM ancestors st
-        JOIN statuses s ON s.id = st.id
-        WHERE st.mention_id IS NOT NULL AND s.visibility = 3
+        FROM ancestors
+        JOIN statuses s ON s.id = ancestors.id
+        WHERE ancestors.mention_id IS NOT NULL AND s.account_id = :recipient_id AND s.visibility = 3
       SQL
     end
   end
diff --git a/spec/services/notify_service_spec.rb b/spec/services/notify_service_spec.rb
index 514f634d7..6064d2b05 100644
--- a/spec/services/notify_service_spec.rb
+++ b/spec/services/notify_service_spec.rb
@@ -309,6 +309,19 @@ RSpec.describe NotifyService do
               expect(subject.filter?).to be false
             end
           end
+
+          context 'when the sender is mentioned in an unrelated message chain' do
+            before do
+              original_status = Fabricate(:status, visibility: :direct)
+              intermediary_status = Fabricate(:status, visibility: :direct, thread: original_status)
+              notification.target_status.update(thread: intermediary_status)
+              Fabricate(:mention, status: original_status, account: notification.from_account)
+            end
+
+            it 'returns true' do
+              expect(subject.filter?).to be true
+            end
+          end
         end
       end
     end