More than 4 accordions – error?

Hi,

I really like your plugin (I'm still using the free version) and I was working on some kind of index. When I create more than 4 accordions, suddenly the 4th and the following accordions have another styling.

Did I miss something or is this done by purpose? Do I need the Pro version to create more than 4?

Here is the site: http://somsolafrica.com/cirro/manifesto/

Thanks in advance for clarification.

Best regards