Perhaps refreshing will help?

Author: Taaku18

bot.py

@@ -202,6 +202,7 @@ async def on_ready(self):
             print(Fore.RED + Style.BRIGHT + 'WARNING - The GUILD_ID provided does not exist!' + Style.RESET_ALL)
         else:
             await self.threads.populate_cache()
+        await self.config.update()
 
         closures = self.config.get('closures', {})
         print(closures)  # for debugging

core/config.py

@@ -43,7 +43,6 @@ def populate_cache(self):
             'blocked': {},
             'notification_squad': {},
             'subscriptions': {},
-            'closures': {}
         }
 
         try:

core/thread.py

@@ -58,6 +58,7 @@ async def close(self, *, closer, after=0, silent=False,
         if after > 0:
             # TODO: Add somewhere to clean up broken closures
             #  (when channel is already deleted)
+            await self.bot.config.update()
             closures = self.bot.config.get('closures', {})
             now = datetime.datetime.utcnow()
             items = {