This sounds particularly relevant:
Apr 15 12:20:28 virgil gnome-shell[4571]: pushModal: invocation of begin_modal failed Apr 15 12:20:28 virgil gnome-shell[4571]: pushModal: invocation of begin_modal failed
which seems to be from gnome-shell/js/ui/main.js
This sounds particularly relevant:
Apr 15 12:20:28 virgil gnome-shell[4571]: pushModal: invocation of begin_modal failed
Apr 15 12:20:28 virgil gnome-shell[4571]: pushModal: invocation of begin_modal failed
which seems to be from gnome-shell/ js/ui/main. js