Upstream we fixed a bug in appstream-glib that means that removing flatpaks works much better. Without this fix you can search for gimp, install (as a flatpak), remove the flatpak, and then you can't see GIMP again in the search results until you restart. This is bad.

The cause of the bug is that the AsStore removes the AsApp when the .desktop file disappears, even if the app still exists elsewhere in the AppStream remote metadata. This bug also manifests itself when you remove an application it *sometimes* does not disappear from the Installed panel. Whether it happens or not with the old version of appstream-glib depends on the ordering we get notified of the files changing, which is also fixed by the same commit.

I'd obviously like to fix this when we enable the flatpak support in gnome-software if possible. We also only figured out and fixed this upstream last week so sorry for the late bug for 7.4. Thanks all!