Fix crash

src/org/thoughtcrime/securesms/loki/api/PublicChatManager.kt

@@ -24,8 +24,8 @@ class PublicChatManager(private val context: Context) {
     var areAllCaughtUp = true
     refreshChatsAndPollers()
     for ((threadID, chat) in chats) {
-      val poller = pollers[threadID] ?: PublicChatPoller(context, chat)
+      val poller = pollers[threadID]
-      areAllCaughtUp = areAllCaughtUp && poller.isCaughtUp
+      areAllCaughtUp = if(poller != null) areAllCaughtUp && poller.isCaughtUp else false
     }
     return areAllCaughtUp
   }