There's an issue in the rendering of Markdown for Bold, Italic or Bold-Italic.
The Markdown clearly specification states that *Italic* should produce italic, **bold** will produce bold, and therefore ***bold-italic*** produces bold-italic .
However, there is code in pen.js that states 'italic' is ***italic*** and bold-italic is **bold-italic** which is wrong (it produces Bold-Italic and Bold respectively).
If you pasted the result of the generated code into any markdown processor it would not reproduce what you'd typed correctly.