Unsure how the fallback is done in the browsers but the issue seems at least due to the theme, yaru doesn't provide those cursors
$ python3 -c "from gi.repository import Gtk,Gdk,GObject; window = Gtk.Window(); window.show_all(); window.get_window().set_cursor(Gdk.Cursor.new_from_name(Gdk.Display.get_default(), 'wait')); Gtk.main()"
Displays the 'wrong' cursor similaring to the snaps
Unsure how the fallback is done in the browsers but the issue seems at least due to the theme, yaru doesn't provide those cursors
$ python3 -c "from gi.repository import Gtk,Gdk,GObject; window = Gtk.Window(); window.show_all(); window. get_window( ).set_cursor( Gdk.Cursor. new_from_ name(Gdk. Display. get_default( ), 'wait')); Gtk.main()"
Displays the 'wrong' cursor similaring to the snaps