diff --git a/telethon/client/updates.py b/telethon/client/updates.py
index ea129cf4..6b35f4c8 100644
--- a/telethon/client/updates.py
+++ b/telethon/client/updates.py
@@ -366,7 +366,7 @@ class EventBuilderDict:
 
         self.client._log[__name__].debug('Getting difference for entities')
         result = await self.client(functions.updates.GetDifferenceRequest(
-            pts, date, 0
+            pts - 1, date, 0
         ))
 
         if isinstance(result, (types.updates.Difference,
diff --git a/telethon/events/callbackquery.py b/telethon/events/callbackquery.py
index 975800e3..1c7c8764 100644
--- a/telethon/events/callbackquery.py
+++ b/telethon/events/callbackquery.py
@@ -101,6 +101,10 @@ class CallbackQuery(EventBuilder):
             self._message = None
             self._answered = False
 
+        def _load_entities(self):
+            self._sender, self._input_sender = self._get_entity_pair(self.sender_id)
+            return super()._load_entities() and self._input_sender is not None
+
         @property
         def id(self):
             """
diff --git a/telethon/events/common.py b/telethon/events/common.py
index db644efd..7940a94a 100644
--- a/telethon/events/common.py
+++ b/telethon/events/common.py
@@ -147,22 +147,31 @@ class EventCommon(ChatGetter, abc.ABC):
         """
         self._client = client
 
+    def _get_entity_pair(self, entity_id):
+        """
+        Returns ``(entity, input_entity)`` for the given entity ID.
+        """
+        entity = self._entities.get(entity_id)
+        try:
+            input_entity = utils.get_input_peer(entity)
+        except TypeError:
+            try:
+                input_entity = self._client._entity_cache[entity_id]
+            except KeyError:
+                input_entity = None
+
+        return entity, input_entity
+
     def _load_entities(self):
         """
         Must load all the entities it needs from cache, and
         return ``False`` if it could not find all of them.
         """
-        # TODO Make sure all subclasses implement this
-        self._chat = self._entities.get(self.chat_id)
-        try:
-            self._input_chat = utils.get_input_peer(self._chat)
-        except TypeError:
-            try:
-                self._input_chat = self._client._entity_cache[self._chat_peer]
-            except KeyError:
-                return False
+        if not self._chat_peer:
+            return True  # Nothing to load (e.g. MessageDeleted)
 
-        return True
+        self._chat, self._input_chat = self._get_entity_pair(self.chat_id)
+        return self._input_chat is not None
 
     @property
     def client(self):
diff --git a/telethon/events/inlinequery.py b/telethon/events/inlinequery.py
index 0655afef..7bd75cc6 100644
--- a/telethon/events/inlinequery.py
+++ b/telethon/events/inlinequery.py
@@ -87,6 +87,10 @@ class InlineQuery(EventBuilder):
             self._input_sender = None
             self._sender = None
 
+        def _load_entities(self):
+            self._sender, self._input_sender = self._get_entity_pair(self.sender_id)
+            return super()._load_entities() and self._input_sender is not None
+
         @property
         def id(self):
             """
diff --git a/telethon/events/newmessage.py b/telethon/events/newmessage.py
index 01f378ef..1b21224f 100644
--- a/telethon/events/newmessage.py
+++ b/telethon/events/newmessage.py
@@ -207,6 +207,13 @@ class NewMessage(EventBuilder):
             self.message._finish_init(client, self._entities, None)
             self.__dict__['_init'] = True  # No new attributes can be set
 
+        def _load_entities(self):
+            m = self.message
+            m._chat, m._input_chat = self._get_entity_pair(m.chat_id)
+            m._sender, m._input_sender = self._get_entity_pair(m.sender_id)
+            return m._input_chat is not None and (
+                    not m.sender_id or m._input_sender is not None)
+
         def __getattr__(self, item):
             if item in self.__dict__:
                 return self.__dict__[item]
diff --git a/telethon/events/userupdate.py b/telethon/events/userupdate.py
index 9d4dab44..93c1a397 100644
--- a/telethon/events/userupdate.py
+++ b/telethon/events/userupdate.py
@@ -185,6 +185,10 @@ class UserUpdate(EventBuilder):
 
             super()._set_client(client)
 
+        def _load_entities(self):
+            self._sender, self._input_sender = self._get_entity_pair(self.sender_id)
+            return super()._load_entities() and self._input_sender is not None
+
         @property
         def user(self):
             """Alias for `sender`."""
diff --git a/telethon/tl/custom/chatgetter.py b/telethon/tl/custom/chatgetter.py
index 8eb904d4..7fdb79a0 100644
--- a/telethon/tl/custom/chatgetter.py
+++ b/telethon/tl/custom/chatgetter.py
@@ -49,7 +49,7 @@ class ChatGetter(abc.ABC):
         """
         if self._input_chat is None and self._chat_peer:
             try:
-                self._input_chat = self._client._entity_cache(self._chat_peer)
+                self._input_chat = self._client._entity_cache[self._chat_peer]
             except KeyError:
                 pass