diff --git a/src/pocketmine/level/Level.php b/src/pocketmine/level/Level.php
index 1ce4ad3fd..15a3e9eb6 100644
--- a/src/pocketmine/level/Level.php
+++ b/src/pocketmine/level/Level.php
@@ -1349,7 +1349,7 @@ class Level implements ChunkManager, Metadatable{
 				}else{
 					$task = new ChunkRequestTask($this, $x, $z);
 					$this->server->getScheduler()->scheduleAsyncTask($task);
-					$this->chunkSendTasks[$index] = $task;
+					$this->chunkSendTasks[$index] = true;
 				}
 			}
 		}
diff --git a/src/pocketmine/scheduler/ServerScheduler.php b/src/pocketmine/scheduler/ServerScheduler.php
index bf6ff4e4d..3f07099a7 100644
--- a/src/pocketmine/scheduler/ServerScheduler.php
+++ b/src/pocketmine/scheduler/ServerScheduler.php
@@ -45,6 +45,9 @@ class ServerScheduler{
 
 	protected $asyncTasks = 0;
 
+	/** @var AsyncTask[] */
+	protected $asyncTaskStorage = [];
+
 	/** @var int */
 	private $ids = 1;
 
@@ -75,6 +78,7 @@ class ServerScheduler{
 	 */
 	public function scheduleAsyncTask(AsyncTask $task){
 		$this->asyncPool->submit($task);
+		$this->asyncTaskStorage[spl_object_hash($task)] = $task;
 		++$this->asyncTasks;
 	}
 
@@ -214,18 +218,21 @@ class ServerScheduler{
 		}
 
 		if($this->asyncTasks > 0){ //Garbage collector
-			$this->asyncPool->collect(function (AsyncTask $task){
-				if($task->isFinished() and !$task->isCompleted()){
-					--$this->asyncTasks;
-					$task->onCompletion(Server::getInstance());
-					$task->setCompleted();
-					return true;
-				}
-				return false;
-			});
+			$this->asyncPool->collect([$this, "collectAsyncTask"]);
 		}
 	}
 
+	public function collectAsyncTask(AsyncTask $task){
+		if($task->isFinished() and !$task->isCompleted()){
+			--$this->asyncTasks;
+			$task->onCompletion(Server::getInstance());
+			$task->setCompleted();
+			unset($this->asyncTaskStorage[spl_object_hash($task)]);
+			return true;
+		}
+		return false;
+	}
+
 	private function isReady($currentTicks){
 		return count($this->tasks) > 0 and $this->queue->current()->getNextRun() <= $currentTicks;
 	}