Program: 55306
Project: 55306
Buggy source:
public static void main(String[] args) throws IOException, InterruptedException {
  YamlLogging.clientWrites=false;
  YamlLogging.clientReads=false;
  YamlLogging.setAll(false);
  ClassAliasPool.CLASS_ALIASES.addAlias(ChronicleMapGroupFS.class);
  ClassAliasPool.CLASS_ALIASES.addAlias(FilePerKeyGroupFS.class);
  WireType writeType=WireType.BINARY;
  char[] x=new char[VALUE_SIZE];
  Arrays.fill(x,'X');
  final String s=new String(x);
  Executors.newSingleThreadExecutor().submit(() -> {
    VanillaAssetTree tree5=new VanillaAssetTree("String_Node_Str").forRemoteAccess("String_Node_Str",WIRE_TYPE);
    final ConcurrentMap<String,String> map1=tree5.acquireMap(NAME,String.class,String.class);
    for (; ; ) {
      for (int i=0; i < entries; i++) {
        try {
          map1.put("String_Node_Str" + i,s);
          Thread.sleep(20);
        }
 catch (        Throwable t) {
          t.printStackTrace();
        }
      }
    }
  }
);
  YamlLogging.setAll(false);
  final ConcurrentMap<String,String> map;
  AssetTree tree3=new VanillaAssetTree("String_Node_Str").forRemoteAccess("String_Node_Str",WIRE_TYPE);
  tree3.acquireMap(NAME,String.class,String.class).size();
  int[] count={0};
  tree3.registerSubscriber(NAME,MapEvent.class,me -> {
    System.out.print((me == null) ? "String_Node_Str" : me.getKey());
    if (++count[0] >= 20) {
      System.out.println();
      count[0]=0;
    }
 else {
      System.out.print("String_Node_Str");
    }
  }
);
  System.in.read();
}

Fixed version (ground truth):
public static void main(String[] args) throws IOException, InterruptedException {
  YamlLogging.clientWrites=false;
  YamlLogging.clientReads=false;
  YamlLogging.setAll(false);
  ClassAliasPool.CLASS_ALIASES.addAlias(ChronicleMapGroupFS.class);
  ClassAliasPool.CLASS_ALIASES.addAlias(FilePerKeyGroupFS.class);
  WireType writeType=WireType.BINARY;
  char[] x=new char[VALUE_SIZE];
  Arrays.fill(x,'X');
  final String s=new String(x);
  Executors.newSingleThreadExecutor().submit(() -> {
    VanillaAssetTree tree5=new VanillaAssetTree("String_Node_Str").forRemoteAccess("String_Node_Str",WIRE_TYPE);
    final ConcurrentMap<String,String> map1=tree5.acquireMap(NAME,String.class,String.class);
    for (; ; ) {
      for (int i=0; i < entries; i++) {
        try {
          map1.put("String_Node_Str" + i,s);
          Thread.sleep(20);
        }
 catch (        Throwable t) {
          t.printStackTrace();
        }
      }
    }
  }
);
  Executors.newSingleThreadExecutor().submit(() -> {
    VanillaAssetTree tree5=new VanillaAssetTree("String_Node_Str").forRemoteAccess("String_Node_Str",WIRE_TYPE);
    final ConcurrentMap<String,String> map1=tree5.acquireMap(NAME,String.class,String.class);
    for (; ; ) {
      for (int i=0; i < entries; i++) {
        try {
          map1.remove("String_Node_Str" + i);
          Thread.sleep(20);
        }
 catch (        Throwable t) {
          t.printStackTrace();
        }
      }
    }
  }
);
  YamlLogging.setAll(false);
  final ConcurrentMap<String,String> map;
  AssetTree tree3=new VanillaAssetTree("String_Node_Str").forRemoteAccess("String_Node_Str",WIRE_TYPE);
  tree3.acquireMap(NAME,String.class,String.class).size();
  int[] count={0};
  tree3.registerSubscriber(NAME,MapEvent.class,me -> {
    System.out.print((me == null) ? "String_Node_Str" : me.getKey());
    if (++count[0] >= 20) {
      System.out.println();
      count[0]=0;
    }
 else {
      System.out.print("String_Node_Str");
    }
  }
);
  System.in.read();
}