Possible UI or View Issue with Emit of Same Key

Set bucket up with a series of documents.

Create a view with the following map function:

function (doc) {
emit("x", null);
}

Note that the UI shows links for the first document only. Either the doc._id in the emit array is being set incorrectly or the UI is displaying the wrong link.

Note that this works (although it introduces the document id into the key):

function (doc) {
emit(["x", doc._id], null);
}