diff --git a/changelogs/3.9.md b/changelogs/3.9.md
index 2f35ab897..9e3e86b75 100644
--- a/changelogs/3.9.md
+++ b/changelogs/3.9.md
@@ -52,3 +52,8 @@ Plugin developers should **only** update their required API to this version if y
 - Fixed `Item->setCustomName()` with an empty string leaving behind an empty tag.
 - Fixed incorrect positioning of bucket empty sound.
 - Fixed some incorrect tag parsing in `/give` involving quoted numbers.
+
+# 3.9.3
+- Fixed a memory leak on async task removal in error conditions.
+- Fixed scheduled block updates (for example liquid) triggering chunk reloading. This could cause a significant performance issue in some conditions.
+- Fixed some minor cosmetic issues in documentation.
diff --git a/src/pocketmine/VersionInfo.php b/src/pocketmine/VersionInfo.php
index d7ae20990..25617f9eb 100644
--- a/src/pocketmine/VersionInfo.php
+++ b/src/pocketmine/VersionInfo.php
@@ -22,6 +22,6 @@
 namespace pocketmine;
 
 const NAME = "PocketMine-MP";
-const BASE_VERSION = "3.9.3";
+const BASE_VERSION = "3.9.4";
 const IS_DEVELOPMENT_BUILD = true;
 const BUILD_NUMBER = 0;
diff --git a/src/pocketmine/level/Level.php b/src/pocketmine/level/Level.php
index 3fb39dc30..9ca2e1af4 100644
--- a/src/pocketmine/level/Level.php
+++ b/src/pocketmine/level/Level.php
@@ -820,7 +820,12 @@ class Level implements ChunkManager, Metadatable{
 
 		//Delayed updates
 		while($this->scheduledBlockUpdateQueue->count() > 0 and $this->scheduledBlockUpdateQueue->current()["priority"] <= $currentTick){
-			$block = $this->getBlock($this->scheduledBlockUpdateQueue->extract()["data"]);
+			/** @var Vector3 $vec */
+			$vec = $this->scheduledBlockUpdateQueue->extract()["data"];
+			if(!$this->isInLoadedTerrain($vec)){
+				continue;
+			}
+			$block = $this->getBlock($vec);
 			unset($this->scheduledBlockUpdateQueueIndex[Level::blockHash($block->x, $block->y, $block->z)]);
 			$block->onScheduledUpdate();
 		}