Theme 52038 portfolio glitch

When selecting a category to view on our portfolio page it’s only showing a few from that category on the first page, and the rest on following pages. Got the portfolio set up to show 9 projects per page so can’t understand why it only shows one or two when viewing a specific category instead of show all?

Ps…show all is working correctly, displaying 9 projects per page.
practech.co.uk