This bug was mentioned in the Ubuntu 18.04.2 release notes as "fixed", however this issue was not fixed in Ubuntu 18.04 and probably won't be.
As far as I know, Joaquim Rocha now works again on GNOME Software at Endless, so we could ask him to provide a better patches, but I don't think the patches will be good enough to include them in Ubuntu (because, unfortunately, even the upstream Flatpak plugin quality was bad in the pre-3.30 GNOME Software).
This bug was mentioned in the Ubuntu 18.04.2 release notes as "fixed", however this issue was not fixed in Ubuntu 18.04 and probably won't be.
As far as I know, Joaquim Rocha now works again on GNOME Software at Endless, so we could ask him to provide a better patches, but I don't think the patches will be good enough to include them in Ubuntu (because, unfortunately, even the upstream Flatpak plugin quality was bad in the pre-3.30 GNOME Software).