Can't add an object to Parse.Relation

After upgrading to Parse 1.6, I get an error that looks like this

Result: ReferenceError: parent is not defined at e.n.value (Parse.js:13:7576)

This is what my code looks like. The error happens at the 'add' call

var author = new Parse.User({id: authorId});
var relation = author.relation("books");
relation.add(book);
author.save();

It just started breaking after I upgraded to Parse 1.6. I've also tried to create the Relation like this, to make sure I set parent:

var relation = new Parse.Relation(author, "books");

But still no luck. Any ideas? Is this broken for anyone else?

Solution

Looks like a confirmed bug that's been sitting around for almost 2 weeks now:

edit... it's been fixed