I've found Nautilus will hang without interacting with it after use. I opened up the Nautilus installed from OpenSuse repos, and the Nautilus installed from Gnome's Nightly Flatpak builds. I was looking at the visual differences between the two (shiny icons! :-O) and after a minute or so, the Nautilus from OpenSuse hung, but the Nightly Flatpak one did not.