JSON.parse not recognizing string arrays

Question

I try to read json content from a file, then parse and output it:

var fs = require('fs');
var data = fs.readFileSync(filename, 'utf8');
var json = JSON.parse(data);
console.log(json);

Case 1

JSON:

{
  "css": {
    "my.css": [
      "MyFolder/MyFile.less"
    ]
  }
}

Output:

{ css: { 'my.css': [ [Circular] ] } }

Case 2

JSON:

{
  "css": {
    "my.css": [
      "MyFolder/MyFile.less",
      "MyFolder/MyOtherFile.less"
    ]
  }
}

Output:

{ css: { 'my.css': [ 'MyFolder/MyFile.less', 'MyFolder/MyOtherFile.less' ] } }

Why do I get [Circular] in Case 1?