Purism app store how to clear cache

I installed gnome-feeds through apt install, but after a while all my feeds were gone and adding new feeds just showed the spinning wheel, so I tried to uninstall via the App Store, but got an error that there were no packages to uninstall. I removed it with apt instead and ran apt autoremove and then reinstalled via apt. Still wouldnt work, so tried to uninstall again from App Store, but same error as before. So uninstalled with apt purge and thought this time I will install it from the App Store. Nope, App Store claims the app is installed (from PureOS repo).

Could the App Store cache be messed up or what else is the problem?