Looking at all the duplicates, this seems to happen only on login. The tiny backtrace in this bug (dups don't have any stacktraces(?)) suggests it's because indicator-appmenu can't connect to dbus and aborts (due to g_error). It's easy enough to make the appmenu not abort in that case, but that wouldn't be very useful. I'm looking into why it might have failed to connect.
Looking at all the duplicates, this seems to happen only on login. The tiny backtrace in this bug (dups don't have any stacktraces(?)) suggests it's because indicator-appmenu can't connect to dbus and aborts (due to g_error). It's easy enough to make the appmenu not abort in that case, but that wouldn't be very useful. I'm looking into why it might have failed to connect.