Following your documented sample, if the <script>s are compressed in the same line:
<html>
<head></head>
<body>
<!-- build:js scripts/combined.js -->
<script type="text/javascript" src="scripts/one.js"></script><script type="text/javascript" src="scripts/two.js"></script>
<!-- endbuild -->
</body>
</html>
It processes only the first file: it does not work!