diff --git a/src/imap.rs b/src/imap.rs
index 9248db7d4f..24117db339 100644
--- a/src/imap.rs
+++ b/src/imap.rs
@@ -1284,6 +1284,9 @@ impl Session {
             context.on_archived_chats_maybe_noticed();
         }
         for updated_chat_id in updated_chat_ids {
+            // NB: There are no other events that remove notifications at least for messages seen on
+            // other devices, so while we may also remove useful notifications for newer messages,
+            // we have no other choice.
             context.emit_event(EventType::MsgsNoticed(updated_chat_id));
             chatlist_events::emit_chatlist_item_changed(context, updated_chat_id);
         }
diff --git a/src/reaction.rs b/src/reaction.rs
index f0f18b2598..a705fafa83 100644
--- a/src/reaction.rs
+++ b/src/reaction.rs
@@ -547,6 +547,32 @@ Here's my footer -- bob@example.net"
         let reactions = get_msg_reactions(&alice, msg.id).await?;
         assert_eq!(reactions.to_string(), "😀1");
 
+        // Alice receives a seen reaction to her message from Bob. Reactions are assigned to the
+        // trash chat and shouldn't cause emitting `MsgsNoticed`.
+        alice.evtracker.clear_events();
+        let seen = true;
+        receive_imf(
+            &alice,
+            "To: alice@example.org\n\
+From: bob@example.net\n\
+Date: Today, 29 February 2021 00:00:10 -800\n\
+Message-ID: 56791@example.net\n\
+In-Reply-To: 12345@example.org\n\
+Subject: Meeting\n\
+Mime-Version: 1.0 (1.0)\n\
+Content-Type: text/plain; charset=utf-8\n\
+Content-Disposition: reaction\n\
+\n\
+\u{1F44D}"
+                .as_bytes(),
+            seen,
+        )
+        .await?;
+        let ev = alice
+            .evtracker
+            .get_matching_opt(&alice, |e| matches!(e, EventType::MsgsNoticed { .. }))
+            .await;
+        assert!(ev.is_none());
         Ok(())
     }
 
diff --git a/src/receive_imf.rs b/src/receive_imf.rs
index 006151306f..6a4e04d51e 100644
--- a/src/receive_imf.rs
+++ b/src/receive_imf.rs
@@ -614,6 +614,9 @@ pub(crate) async fn receive_imf_inner(
             chat_id.emit_msg_event(context, *msg_id, mime_parser.incoming && fresh);
         }
     }
+    if !chat_id.is_trash() && received_msg.state == MessageState::InSeen {
+        context.emit_event(EventType::MsgsNoticed(chat_id));
+    }
     context.new_msgs_notify.notify_one();
 
     mime_parser
diff --git a/src/receive_imf/tests.rs b/src/receive_imf/tests.rs
index 398471719e..515a09dea8 100644
--- a/src/receive_imf/tests.rs
+++ b/src/receive_imf/tests.rs
@@ -269,6 +269,31 @@ async fn test_adhoc_groups_merge() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_msgs_noticed_on_seen_msg() -> Result<()> {
+    let mut tcm = TestContextManager::new();
+    let alice = &tcm.alice().await;
+    let seen = true;
+    let rcvd_msg = receive_imf(
+        alice,
+        b"From: bob@example.net\n\
+        To: alice@example.org\n\
+        Message-ID: <3333@example.net>\n\
+        Date: Sun, 22 Mar 2020 22:37:57 +0000\n\
+        \n\
+        This is a seen message.\n",
+        seen,
+    )
+    .await?
+    .unwrap();
+    let ev = alice
+        .evtracker
+        .get_matching(|e| matches!(e, EventType::MsgsNoticed { .. }))
+        .await;
+    assert_eq!(ev, EventType::MsgsNoticed(rcvd_msg.chat_id));
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_read_receipt_and_unarchive() -> Result<()> {
     // create alice's account
@@ -3009,6 +3034,35 @@ async fn test_read_receipts_dont_unmark_bots() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_no_msgs_noticed_on_seen_mdn() -> Result<()> {
+    let mut tcm = TestContextManager::new();
+    let alice = &tcm.alice().await;
+    let bob = &tcm.bob().await;
+
+    let received_msg = tcm.send_recv_accept(alice, bob, "hi").await;
+
+    let mdn_mimefactory = crate::mimefactory::MimeFactory::from_mdn(
+        bob,
+        received_msg.from_id,
+        received_msg.rfc724_mid,
+        vec![],
+    )
+    .await?;
+    let rendered_mdn = mdn_mimefactory.render(bob).await?;
+    let mdn_body = rendered_mdn.message;
+
+    let seen = true;
+    alice.evtracker.clear_events();
+    receive_imf(alice, mdn_body.as_bytes(), seen).await?;
+    let ev = alice
+        .evtracker
+        .get_matching_opt(alice, |e| matches!(e, EventType::MsgsNoticed { .. }))
+        .await;
+    assert!(ev.is_none());
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_gmx_forwarded_msg() -> Result<()> {
     let t = TestContext::new_alice().await;