ExpressJS 3.2 renders blank pages sometimes

I just upgraded to Express 3.2.4. It works fine, but sometimes (actually, quite frequently) renders a blank page. There is no error, response status is 200, but there is no response body.

It does this with every view, including those using only a simple res.send('somestring') call. Sometimes "somestring" appears in the browser, but mostly it just shows a blank page.

Any ideas about why this is happening? The same code worked fine with Express 2.5.9, and Express is the only node module I updated

Any help would be appreciated!

Thanks in advance

EDIT:

I'm using NodeJS 0.10.2 and the SWIG template engine (via ConsolidateJS).

An example:

some: function(req, res) {

    res.send('some text');

},