diff --git a/pom.xml b/pom.xml
index 725f292..70bd7f0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -67,7 +67,7 @@
         <!-- Do not change unless you want different name for local builds. -->
         <build.number>-LOCAL</build.number>
         <!-- This allows to change between versions. -->
-        <build.version>1.24.0</build.version>
+        <build.version>1.25.0</build.version>
         <!-- SonarCloud -->
         <sonar.projectKey>BentoBoxWorld_AOneBlock</sonar.projectKey>
         <sonar.organization>bentobox-world</sonar.organization>
diff --git a/src/main/java/world/bentobox/aoneblock/listeners/BlockListener.java b/src/main/java/world/bentobox/aoneblock/listeners/BlockListener.java
index c066b98..8cb522c 100644
--- a/src/main/java/world/bentobox/aoneblock/listeners/BlockListener.java
+++ b/src/main/java/world/bentobox/aoneblock/listeners/BlockListener.java
@@ -527,12 +527,18 @@ private void processNextBlock(Cancellable e, Island i, Player player, Block bloc
      * @param nextBlock - next block object containing entity info
      */
     private void handleEntitySpawn(Cancellable e, Island i, Player player, Block block, OneBlockObject nextBlock) {
-        if (!(e instanceof EntitySpawnEvent)) {
+        boolean cancelled = !(e instanceof EntitySpawnEvent);
+        if (cancelled) {
             e.setCancelled(true);
         }
         spawnEntity(nextBlock, block);
+        // Cancelling BlockBreakEvent at HIGHEST priority leaves the client with a
+        // mispredicted "block gone" state; resync the actual block to clear it.
+        if (cancelled && player != null) {
+            player.sendBlockChange(block.getLocation(), block.getBlockData());
+        }
         Bukkit.getPluginManager().callEvent(new MagicBlockEntityEvent(i,
-                player == null ? null : player.getUniqueId(), 
+                player == null ? null : player.getUniqueId(),
                         block, nextBlock.getEntityType()));
     }
 
@@ -886,7 +892,14 @@ private void fillChest(@NonNull OneBlockObject nextBlock, @NonNull Block block)
             return;
         }
         Color color = addon.getSettings().resolveChestColor(rarity);
-        Object particleData = Particle.DUST.equals(particle) ? new Particle.DustOptions(color, 1) : null;
+        Object particleData = null;
+        if (Particle.DUST.equals(particle)) {
+            particleData = new Particle.DustOptions(color, 1);
+        } else if (!Void.class.equals(particle.getDataType())) {
+            // Particle requires typed data we can't provide — skip rather than crash
+            addon.logWarning("Chest particle " + particle.name() + " requires extra data and cannot be used. Use DUST or a void-data particle.");
+            return;
+        }
         block.getWorld().spawnParticle(particle, block.getLocation().add(new Vector(0.5, 1.0, 0.5)), 50, 0.5,
                 0, 0.5, 1, particleData);
     }
diff --git a/src/main/java/world/bentobox/aoneblock/oneblocks/customblock/CraftEngineCustomBlock.java b/src/main/java/world/bentobox/aoneblock/oneblocks/customblock/CraftEngineCustomBlock.java
index 0c31d30..bd5b022 100644
--- a/src/main/java/world/bentobox/aoneblock/oneblocks/customblock/CraftEngineCustomBlock.java
+++ b/src/main/java/world/bentobox/aoneblock/oneblocks/customblock/CraftEngineCustomBlock.java
@@ -1,7 +1,6 @@
 package world.bentobox.aoneblock.oneblocks.customblock;
 
 import java.util.Map;
-import java.util.Objects;
 import java.util.Optional;
 
 import org.bukkit.Material;
@@ -26,10 +25,29 @@ public static Optional<CraftEngineCustomBlock> fromId(String id) {
         return Optional.empty();
     }
 
+    /**
+     * Checks whether {@code id} is a syntactically valid namespaced key
+     * ({@code namespace:key} with both parts non-blank).
+     */
+    static boolean isValidNamespacedKey(String id) {
+        int colon = id.indexOf(':');
+        if (colon <= 0 || colon == id.length() - 1) {
+            return false;
+        }
+        String namespace = id.substring(0, colon);
+        String key = id.substring(colon + 1);
+        return !namespace.isBlank() && !key.isBlank();
+    }
+
     public static Optional<CraftEngineCustomBlock> fromMap(Map<?, ?> map) {
-        return Optional
-                .ofNullable(Objects.toString(map.get("id"), null))
-                .flatMap(CraftEngineCustomBlock::fromId);
+        Object raw = map.get("id");
+        if (!(raw instanceof String id)) {
+            return Optional.empty();
+        }
+        if (id.isBlank() || !isValidNamespacedKey(id)) {
+            return Optional.empty();
+        }
+        return Optional.of(new CraftEngineCustomBlock(id));
     }
 
     @Override
diff --git a/src/main/resources/phases/8500_plenty.yml b/src/main/resources/phases/8500_plenty.yml
index 758153f..0615f37 100644
--- a/src/main/resources/phases/8500_plenty.yml
+++ b/src/main/resources/phases/8500_plenty.yml
@@ -45,6 +45,10 @@
     DIRT_PATH: 1
     LIGHT_GRAY_TERRACOTTA: 1
     SUSPICIOUS_SAND: 1
+  custom-blocks:
+    - type: block
+      data: 'minecraft:bee_nest[honey_level=0,facing=north]{bees:[{entity_data:{id:"minecraft:bee"},min_ticks_in_hive:600,ticks_in_hive:0},{entity_data:{id:"minecraft:bee"},min_ticks_in_hive:600,ticks_in_hive:0},{entity_data:{id:"minecraft:bee"},min_ticks_in_hive:600,ticks_in_hive:0}]}'
+      probability: 1
   mobs:
     COW: 1
     DONKEY: 1
diff --git a/src/test/java/world/bentobox/aoneblock/oneblocks/customblock/CraftEngineCustomBlockTest.java b/src/test/java/world/bentobox/aoneblock/oneblocks/customblock/CraftEngineCustomBlockTest.java
index cd35d31..2d91929 100644
--- a/src/test/java/world/bentobox/aoneblock/oneblocks/customblock/CraftEngineCustomBlockTest.java
+++ b/src/test/java/world/bentobox/aoneblock/oneblocks/customblock/CraftEngineCustomBlockTest.java
@@ -1,5 +1,7 @@
 package world.bentobox.aoneblock.oneblocks.customblock;
 
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.LinkedHashMap;
@@ -27,4 +29,122 @@ void fromMapReturnsEmptyWhenIdMissing() {
 
         assertTrue(result.isEmpty(), "Should return empty when 'id' is missing");
     }
+
+    @Test
+    void fromMapReturnsEmptyWhenIdIsNull() {
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("type", "craftengine");
+        map.put("id", null);
+
+        var result = CraftEngineCustomBlock.fromMap(map);
+
+        assertTrue(result.isEmpty(), "Should return empty when 'id' is null");
+    }
+
+    @Test
+    void fromMapReturnsEmptyWhenIdIsBlank() {
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("type", "craftengine");
+        map.put("id", "   ");
+
+        var result = CraftEngineCustomBlock.fromMap(map);
+
+        assertTrue(result.isEmpty(), "Should return empty when 'id' is blank");
+    }
+
+    @Test
+    void fromMapReturnsEmptyWhenIdIsNonStringValue() {
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("type", "craftengine");
+        map.put("id", 42); // integer, not a String
+
+        var result = CraftEngineCustomBlock.fromMap(map);
+
+        assertTrue(result.isEmpty(), "Should return empty when 'id' is not a String");
+    }
+
+    @Test
+    void fromMapReturnsEmptyWhenIdHasNoColon() {
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("type", "craftengine");
+        map.put("id", "nocolon");
+
+        var result = CraftEngineCustomBlock.fromMap(map);
+
+        assertTrue(result.isEmpty(), "Should return empty when 'id' has no colon");
+    }
+
+    @Test
+    void fromMapReturnsEmptyWhenIdHasEmptyNamespace() {
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("type", "craftengine");
+        map.put("id", ":key");
+
+        var result = CraftEngineCustomBlock.fromMap(map);
+
+        assertTrue(result.isEmpty(), "Should return empty when namespace part is empty");
+    }
+
+    @Test
+    void fromMapReturnsEmptyWhenIdHasEmptyKey() {
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("type", "craftengine");
+        map.put("id", "namespace:");
+
+        var result = CraftEngineCustomBlock.fromMap(map);
+
+        assertTrue(result.isEmpty(), "Should return empty when key part is empty");
+    }
+
+    /**
+     * {@code fromMap} must succeed even when CraftEngine has not yet loaded its
+     * block registry (i.e. without calling {@code CraftEngineHook.exists}).
+     * This prevents false "Bad custom block" errors during the initial server
+     * start-up phase that occurs before CraftEngine fires its reload event.
+     */
+    @Test
+    void fromMapReturnsPresentWhenIdProvided() {
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("type", "craftengine");
+        map.put("id", "oneblock:common_loot_block");
+        map.put("probability", 300);
+
+        var result = CraftEngineCustomBlock.fromMap(map);
+
+        assertTrue(result.isPresent(), "Should return a block when 'id' is present, regardless of CraftEngine load state");
+        assertInstanceOf(CraftEngineCustomBlock.class, result.get());
+    }
+
+    // --- isValidNamespacedKey helper tests ---
+
+    @Test
+    void isValidNamespacedKeyReturnsTrueForValidKey() {
+        assertTrue(CraftEngineCustomBlock.isValidNamespacedKey("ns:key"));
+        assertTrue(CraftEngineCustomBlock.isValidNamespacedKey("oneblock:common_loot_block"));
+    }
+
+    @Test
+    void isValidNamespacedKeyReturnsFalseForMissingColon() {
+        assertFalse(CraftEngineCustomBlock.isValidNamespacedKey("nocolon"));
+    }
+
+    @Test
+    void isValidNamespacedKeyReturnsFalseForLeadingColon() {
+        assertFalse(CraftEngineCustomBlock.isValidNamespacedKey(":key"));
+    }
+
+    @Test
+    void isValidNamespacedKeyReturnsFalseForTrailingColon() {
+        assertFalse(CraftEngineCustomBlock.isValidNamespacedKey("ns:"));
+    }
+
+    @Test
+    void isValidNamespacedKeyReturnsFalseForBlankNamespace() {
+        assertFalse(CraftEngineCustomBlock.isValidNamespacedKey("   :key"));
+    }
+
+    @Test
+    void isValidNamespacedKeyReturnsFalseForBlankKey() {
+        assertFalse(CraftEngineCustomBlock.isValidNamespacedKey("ns:   "));
+    }
 }