Many applications are duplicated in installed view
In gnome-software-3.32.0-3.fc30, in the Installed software view, Software displays a bunch of duplicate apps. Contacts and GIMP are both duplicated, for example. It's not clear what is going on here. There are multiple software sources available, but the duplication does not appear to correspond to multiple sources.
The screencast also shows duplicated Epiphany, but that one can probably be ignored as that is intentionally split into stable and devel channels. (I have Epiphany Technology Preview installed.)
When clicking the checkbox in the upper right, even more duplicate apps appear. These apps do not have any app icon. For example, Builder only appears once until I click the checkbox, then a second Builder appears. Same for Geary and several games: