Views not showing all nodes if filtered by taxonomy term

Hello, I have a test accordion view here:

http://www.lwec.org.uk/_dev/accordion_prototype

Although the page shows 23 nodes, there are more than 30, changing the number of taxonomy terms to render seems to randomly decrease the number of nodes shown but never on the same number as in the taxonomy.

Any help will be greatly appreciated.

Cheers

Javier