Outputs only a small vertical bar

There was something I could do 🙂

I found a page where this plugin worked and looked at the page source.
The difference was striking. Many lines were embedded in < p > …. < / p > tags. (sry – remove the spaces, I fear leaving them in will screw this post up).
By formatting the rps shortcode as “preformatted” it works again.
So select the text [ rps ] and choose “preformatted” and you are good to go. Wouldn’t call this a fix, but it surely is a workaround.