Discover from git master in Neon dev unstable. Installing any Flatpak app from Flathub (I tried several) results in the installation progress bars starting at 100% and not moving. Launching Discover from the CLI reveals the following output while installing: progress 100 progress 100 progress 100 progress 100 progress 100 progress 100 progress 100 progress 100 progress 100 progress 100 It starts at 100 and stays there for the duration of the installation.
This was an issue upstream, which I fixed few weeks ago. It will eventually trickle in. https://github.com/flatpak/flatpak/commit/b6eddbccffce5e4e400901ddb2082b6b65e5d4d5