I can't unhide my purchases

I have a handful of purchases which are hidden (no idea how the became hidden in the first place, but that's a different matter altogether), and I can't get them to unhide. I go to the page with the option to unhide, click unhide, and nothing happens. I managed to unhide about 3/4 of my purchases by doing them one by one, but there are still a bunch that I can't unhide. This is the case on my Windows 7 PC and my MacBook Pro (now running El Capitan, but issue started when I was running Yosemite).

Any clues?