fix: deduplicate entity creates

server/traits/informed.trait.js

@@ -43,6 +43,25 @@ export class Informed extends decorate(Trait) {
     );
   }
 
+  deduplicateEntityCreatePackets(packets) {
+    const created = new Map();
+    return packets.filter((packet) => {
+      const entity = packet.entity;
+      if (!entity) {
+        return true;
+      }
+      // Only care about creates.
+      if (!(packet instanceof EntityCreatePacket)) {
+        return true;
+      }
+      if (created.has(entity)) {
+        return false;
+      }
+      created.set(entity, true);
+      return true;
+    });
+  }
+
   filterInvisibleEntityPackets(packets) {
     return packets.filter((packet) => {
       const entity = packet.entity;
@@ -267,6 +286,8 @@ export class Informed extends decorate(Trait) {
           packets,
           outOfRangeEntities
         );
+        // Deduplicate entity creates.
+        packets = this.deduplicateEntityCreatePackets(packets);
         // Filter known creates.
         packets = this.filterKnownEntityCreatePackets(packets);
         // Inject create packets.