Code blocks not working after page render

[dandandandan81]

Codeblocks have stopped working for me, I believe since updating to 2.5.308

Using the example from the formatting guide:

```js
function main () {
 echo 'Lorem ipsum'
}
```

Everything looks correct in the editor, but the rendered page will display a code block but the content is:

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]