diff --git a/EvoScientist/channels/base.py b/EvoScientist/channels/base.py
index 61938e2..1906a8f 100644
--- a/EvoScientist/channels/base.py
+++ b/EvoScientist/channels/base.py
@@ -865,7 +865,7 @@ class Channel(ChannelPlugin, ABC):
 
         Convenience method for subclass ``_on_message`` handlers.
         """
-        msg = self._build_inbound(raw)
+        msg = await self._build_inbound_async(raw)
         if msg is None:
             return
         if raw.message_id:
diff --git a/EvoScientist/channels/dingtalk/channel.py b/EvoScientist/channels/dingtalk/channel.py
index 1b1bffb..d61c9e0 100644
--- a/EvoScientist/channels/dingtalk/channel.py
+++ b/EvoScientist/channels/dingtalk/channel.py
@@ -347,7 +347,7 @@ class DingTalkChannel(Channel, WebSocketMixin, TokenMixin):
                 pass
             self._ws_task = None
         await self._stop_ws()
-        if self._http_client:
+        if hasattr(self, "_http_client") and self._http_client:
             await self._http_client.aclose()
             self._http_client = None
         self._access_token = None
diff --git a/EvoScientist/channels/email/channel.py b/EvoScientist/channels/email/channel.py
index 1336a07..b36eae0 100644
--- a/EvoScientist/channels/email/channel.py
+++ b/EvoScientist/channels/email/channel.py
@@ -81,7 +81,7 @@ class EmailChannel(Channel, PollingMixin):
         cfg = self.config
         if not cfg.imap_host or not cfg.imap_username:
             raise ChannelError("Email imap_host and imap_username are required")
-        loop = asyncio.get_event_loop()
+        loop = asyncio.get_running_loop()
         await loop.run_in_executor(None, self._connect_imap)
         self._running = True
         logger.info(f"Email channel started (IMAP: {cfg.imap_host}, poll {cfg.poll_interval}s)")
@@ -120,7 +120,7 @@ class EmailChannel(Channel, PollingMixin):
         self._connect_imap()
 
     async def _poll_once(self) -> None:
-        loop = asyncio.get_event_loop()
+        loop = asyncio.get_running_loop()
         messages = await loop.run_in_executor(None, self._fetch_unseen)
         for m in messages:
             await self._process_email(m)
@@ -270,7 +270,7 @@ class EmailChannel(Channel, PollingMixin):
                         pass
 
     async def _send_chunk(self, chat_id, formatted_text, raw_text, reply_to, metadata):
-        loop = asyncio.get_event_loop()
+        loop = asyncio.get_running_loop()
         try:
             await loop.run_in_executor(
                 None, self._smtp_send_html, chat_id, formatted_text, raw_text, metadata or {},
@@ -339,7 +339,7 @@ class EmailChannel(Channel, PollingMixin):
         metadata: dict | None = None,
     ) -> bool:
         """Send a file as an email attachment via SMTP."""
-        loop = asyncio.get_event_loop()
+        loop = asyncio.get_running_loop()
         await loop.run_in_executor(
             None, self._smtp_send_attachment, recipient, file_path, caption, metadata or {},
         )
diff --git a/EvoScientist/channels/qq/channel.py b/EvoScientist/channels/qq/channel.py
index 35b47e0..5f6cd82 100644
--- a/EvoScientist/channels/qq/channel.py
+++ b/EvoScientist/channels/qq/channel.py
@@ -69,6 +69,7 @@ class QQChannel(Channel):
         self._processed_ids: deque = deque(maxlen=1000)
         self._msg_seq: dict[str, int] = {}  # msg_id -> next seq number
         self._msg_seq_order: deque = deque(maxlen=500)
+        self._msg_seq_ids: set[str] = set()  # companion set for O(1) lookup
 
     # ── Lifecycle ─────────────────────────────────────────────────
 
@@ -167,10 +168,12 @@ class QQChannel(Channel):
         """Return the next msg_seq for *msg_id* and increment the counter."""
         seq = self._msg_seq.get(msg_id, 1)
         self._msg_seq[msg_id] = seq + 1
-        if msg_id not in set(self._msg_seq_order):
+        if msg_id not in self._msg_seq_ids:
             self._msg_seq_order.append(msg_id)
+            self._msg_seq_ids.add(msg_id)
             if len(self._msg_seq_order) > 500:
                 oldest = self._msg_seq_order.popleft()
+                self._msg_seq_ids.discard(oldest)
                 self._msg_seq.pop(oldest, None)
         return seq
 
diff --git a/EvoScientist/channels/signal/channel.py b/EvoScientist/channels/signal/channel.py
index e21986b..a918e55 100644
--- a/EvoScientist/channels/signal/channel.py
+++ b/EvoScientist/channels/signal/channel.py
@@ -45,6 +45,7 @@ class SignalChannel(Channel):
         # Cache message_id → sender for reaction targetAuthor (bounded)
         self._msg_senders: dict[str, str] = {}
         self._msg_senders_order: deque = deque(maxlen=200)
+        self._listen_task: asyncio.Task | None = None
 
     async def start(self) -> None:
         if not self.config.phone_number:
@@ -69,7 +70,7 @@ class SignalChannel(Channel):
         self._listen_task = asyncio.create_task(self._listen_loop())
 
     async def _cleanup(self) -> None:
-        if hasattr(self, "_listen_task") and self._listen_task:
+        if self._listen_task:
             self._listen_task.cancel()
             self._listen_task = None
         # Cancel any pending RPC futures
@@ -180,7 +181,8 @@ class SignalChannel(Channel):
                     try:
                         await self._connect()
                     except Exception:
-                        pass
+                        logger.warning("Signal reconnect failed, exiting listen loop")
+                        break
 
     async def _handle_rpc(self, data: dict) -> None:
         """Handle a JSON RPC message from signal-cli."""