diff --git a/aiocraft/dispatcher.py b/aiocraft/dispatcher.py
index 9aebbfe..1a005ab 100644
--- a/aiocraft/dispatcher.py
+++ b/aiocraft/dispatcher.py
@@ -228,7 +228,8 @@ class Dispatcher:
 						buffer = io.BytesIO(decompressed_data)
 
 				packet_id = VarInt.read(buffer)
-				if self._packet_id_whitelist and packet_id in self._packet_id_whitelist:
+				if self.state == ConnectionState.PLAY and self._packet_id_whitelist \
+				and packet_id not in self._packet_id_whitelist:
 					self._logger.debug("[<--] Received | Packet(0x%02x) (ignored)", packet_id)
 					continue # ignore this packet, we rarely need them all, should improve performance
 				cls = self._packet_type_from_registry(packet_id)
diff --git a/aiocraft/traits/callbacks.py b/aiocraft/traits/callbacks.py
index 14ad8f3..6bd2499 100644
--- a/aiocraft/traits/callbacks.py
+++ b/aiocraft/traits/callbacks.py
@@ -2,6 +2,7 @@ import asyncio
 import uuid
 import logging
 
+from inspect import isclass
 from typing import Dict, List, Set, Any, Callable, Type
 
 class CallbacksHolder:
@@ -17,7 +18,7 @@ class CallbacksHolder:
 		self._tasks = {}
 
 	def callback_keys(self, filter:Type = None) -> Set[Any]:
-		return set(x for x in self._callbacks.keys() if not filter or issubclass(x, filter))
+		return set(x for x in self._callbacks.keys() if not filter or (isclass(x) and issubclass(x, filter)))
 
 	def register(self, key:Any, callback:Callable):
 		if key not in self._callbacks: