diff --git a/paper-server/nms-patches/WorldServer.patch b/paper-server/nms-patches/WorldServer.patch
index 33f4a40308..b1baf9aec2 100644
--- a/paper-server/nms-patches/WorldServer.patch
+++ b/paper-server/nms-patches/WorldServer.patch
@@ -504,7 +504,27 @@
                  if (d0 * d0 + d1 * d1 + d2 * d2 < 1024.0D) {
                      entityplayer.playerConnection.sendPacket(new PacketPlayOutBlockBreakAnimation(i, blockposition, j));
                  }
-@@ -995,10 +1185,20 @@
+@@ -973,7 +1163,18 @@
+             Iterator iterator = this.navigators.iterator();
+ 
+             while (iterator.hasNext()) {
+-                NavigationAbstract navigationabstract = (NavigationAbstract) iterator.next();
++                // CraftBukkit start - fix SPIGOT-6362
++                NavigationAbstract navigationabstract;
++                try {
++                    navigationabstract = (NavigationAbstract) iterator.next();
++                } catch (java.util.ConcurrentModificationException ex) {
++                    // This can happen because the pathfinder update below may trigger a chunk load, which in turn may cause more navigators to register
++                    // In this case we just run the update again across all the iterators as the chunk will then be loaded
++                    // As this is a relative edge case it is much faster than copying navigators (on either read or write)
++                    notify(blockposition, iblockdata, iblockdata1, i);
++                    return;
++                }
++                // CraftBukkit end
+ 
+                 if (!navigationabstract.i()) {
+                     navigationabstract.b(blockposition);
+@@ -995,10 +1196,20 @@
  
      @Override
      public Explosion createExplosion(@Nullable Entity entity, @Nullable DamageSource damagesource, @Nullable ExplosionDamageCalculator explosiondamagecalculator, double d0, double d1, double d2, float f, boolean flag, Explosion.Effect explosion_effect) {
@@ -525,7 +545,7 @@
          if (explosion_effect == Explosion.Effect.NONE) {
              explosion.clearBlocks();
          }
-@@ -1063,13 +1263,20 @@
+@@ -1063,13 +1274,20 @@
      }
  
      public <T extends ParticleParam> int a(T t0, double d0, double d1, double d2, int i, double d3, double d4, double d5, double d6) {
@@ -548,7 +568,7 @@
                  ++j;
              }
          }
-@@ -1111,7 +1318,7 @@
+@@ -1111,7 +1329,7 @@
  
      @Nullable
      public BlockPosition a(StructureGenerator<?> structuregenerator, BlockPosition blockposition, int i, boolean flag) {
@@ -557,7 +577,7 @@
      }
  
      @Nullable
-@@ -1149,7 +1356,13 @@
+@@ -1149,7 +1367,13 @@
      @Override
      public WorldMap a(String s) {
          return (WorldMap) this.getMinecraftServer().E().getWorldPersistentData().b(() -> {
@@ -572,7 +592,7 @@
          }, s);
      }
  
-@@ -1460,6 +1673,11 @@
+@@ -1460,6 +1684,11 @@
      @Override
      public void update(BlockPosition blockposition, Block block) {
          if (!this.isDebugWorld()) {
@@ -584,7 +604,7 @@
              this.applyPhysics(blockposition, block);
          }
  
-@@ -1474,12 +1692,12 @@
+@@ -1474,12 +1703,12 @@
      }
  
      public boolean isFlatWorld() {
@@ -599,7 +619,7 @@
      }
  
      @Nullable
-@@ -1499,9 +1717,9 @@
+@@ -1499,9 +1728,9 @@
  
      @VisibleForTesting
      public String F() {
@@ -611,7 +631,7 @@
              return IRegistry.BLOCK_ENTITY_TYPE.getKey(tileentity.getTileType());
          }), this.getBlockTickList().a(), this.getFluidTickList().a(), this.P());
      }
-@@ -1509,7 +1727,7 @@
+@@ -1509,7 +1738,7 @@
      private static <T> String a(Collection<T> collection, Function<T, MinecraftKey> function) {
          try {
              Object2IntOpenHashMap<MinecraftKey> object2intopenhashmap = new Object2IntOpenHashMap();
@@ -620,7 +640,7 @@
  
              while (iterator.hasNext()) {
                  T t0 = iterator.next();
-@@ -1518,7 +1736,8 @@
+@@ -1518,7 +1747,8 @@
                  object2intopenhashmap.addTo(minecraftkey, 1);
              }
  
@@ -630,7 +650,7 @@
                  return it_unimi_dsi_fastutil_objects_object2intmap_entry.getKey() + ":" + it_unimi_dsi_fastutil_objects_object2intmap_entry.getIntValue();
              }).collect(Collectors.joining(","));
          } catch (Exception exception) {
-@@ -1527,16 +1746,32 @@
+@@ -1527,16 +1757,32 @@
      }
  
      public static void a(WorldServer worldserver) {