captcha is broken for comments on On Demand Documentation

I've submitted multiple comments to this documentation page: https://confluence.atlassian.com/display/AOD/Atlassian+OnDemand+release+summary

Every time I try to submit a comment, the captcha fails (usually multiple times) before I can successfully submit a comment.

There are also multiple comments about the captcha not working in the comments on the page.

This seems like a great strategy to discourage people from commenting, but a bad strategy if you actually want feedback.