Q: iPad won't re-download certain deleted apps?

My iPad mini has stopped downloading certain already purchased apps from the App Store. If I click the download button (the cloud/arrow icon) it turns into the downloading circle like normal but then immediately reverts back to the cloud. It's not all apps that I've deleted and want to download again. It doesn't matter if I'm in the App Store proper or the Purchased section.

I've rebooted my iPad, freed up more space, signed out and back into my iTunes account, and updated iOS- nothing is fixing the problem. What is going on?