`literal` author not written correctly (bibtex)

[KMIJPH]

Reading this entry:

@misc{agency,
  author = {{European Environment Agency}},
}

to json AST correctly parses it as literal.

...
            "author": {
              "t": "MetaList",
              "c": [
                {
                  "t": "MetaMap",
                  "c": {
                    "literal": {
                      "t": "MetaString",
                      "c": "European Environment Agency"
                    }
...

However, when writing it back to bibtex/biblatex it loses the curly braces, thus not making it literal anymore.

@misc{agency,
  author = {European Environment Agency}
}