FAQ appears twice

I have three FAQ categories: helpingus, gettinghelp, aboutus.

I use these shortcodes to display them:

[ultimate-faqs include_category=’helpingus’]
[ultimate-faqs include_category=’aboutus’]
[ultimate-faqs include_category=’gettinghelp’]

The first two work perfectly.
The last one worked fine when I first did it, but today it repeats the list.

You can see this in action here:
http://lutonfoodbank.org.uk/faq/all-faq/helping-us-faq/
http://lutonfoodbank.org.uk/faq/all-faq/about-us-faq/
http://lutonfoodbank.org.uk/faq/all-faq/getting-help-faq/

The shortcode [ultimate-faqs ] works fine, with no items repeated.

Any idea what’s going on?