diff --git a/nms-patches/WorldServer.patch b/nms-patches/WorldServer.patch
index 5acbfbdab9..be617f4132 100644
--- a/nms-patches/WorldServer.patch
+++ b/nms-patches/WorldServer.patch
@@ -507,7 +507,7 @@
              Iterator iterator = arraylist.iterator();
  
              while (iterator.hasNext()) {
-@@ -695,8 +920,12 @@
+@@ -695,12 +920,37 @@
          this.worldData.k(this.getWorldBorder().getWarningTime());
          this.worldData.b(this.getWorldBorder().j());
          this.worldData.e(this.getWorldBorder().i());
@@ -521,7 +521,32 @@
      }
  
      protected void a(Entity entity) {
-@@ -728,8 +957,16 @@
+         super.a(entity);
++        // CraftBukkit start
++        UUID uuid = entity.getUniqueID();
++
++        if (this.entitiesByUUID.containsKey(uuid)) {
++            Entity entity1 = (Entity) this.entitiesByUUID.get(uuid);
++
++            if (this.g.contains(entity1)) {
++                WorldServer.a.warn("Tried to add entity " + EntityTypes.b(entity1) + " with pending removal and duplicate UUID " + uuid.toString());
++                this.g.remove(entity1);
++            } else {
++                if (!(entity instanceof EntityHuman)) {
++                    WorldServer.a.warn("Keeping entity " + EntityTypes.b(entity1) + " that already exists with UUID " + uuid.toString());
++                    return;
++                }
++
++                WorldServer.a.warn("Force-added player with duplicate UUID " + uuid.toString());
++            }
++
++            this.removeEntity(entity1);
++        }
++        // CraftBukkit end
+         this.entitiesById.a(entity.getId(), entity);
+         this.entitiesByUUID.put(entity.getUniqueID(), entity);
+         Entity[] aentity = entity.aB();
+@@ -728,8 +978,16 @@
      }
  
      public boolean strikeLightning(Entity entity) {
@@ -539,7 +564,7 @@
              return true;
          } else {
              return false;
-@@ -741,10 +978,20 @@
+@@ -741,10 +999,20 @@
      }
  
      public Explosion createExplosion(Entity entity, double d0, double d1, double d2, float f, boolean flag, boolean flag1) {
@@ -560,7 +585,7 @@
          if (!flag1) {
              explosion.clearBlocks();
          }
-@@ -790,7 +1037,8 @@
+@@ -790,7 +1058,8 @@
                  BlockActionData blockactiondata = (BlockActionData) iterator.next();
  
                  if (this.a(blockactiondata)) {
@@ -570,7 +595,7 @@
                  }
              }
  
-@@ -813,6 +1061,7 @@
+@@ -813,6 +1082,7 @@
          boolean flag = this.S();
  
          super.p();
@@ -578,7 +603,7 @@
          if (this.o != this.p) {
              this.server.getPlayerList().a(new PacketPlayOutGameStateChange(7, this.p), this.worldProvider.getDimension());
          }
-@@ -831,6 +1080,21 @@
+@@ -831,6 +1101,21 @@
              this.server.getPlayerList().sendAll(new PacketPlayOutGameStateChange(7, this.p));
              this.server.getPlayerList().sendAll(new PacketPlayOutGameStateChange(8, this.r));
          }
@@ -600,7 +625,7 @@
  
      }
  
-@@ -859,10 +1123,17 @@
+@@ -859,10 +1144,17 @@
      }
  
      public void a(EnumParticle enumparticle, boolean flag, double d0, double d1, double d2, int i, double d3, double d4, double d5, double d6, int... aint) {