Comment 4 for bug 435692

I modified /etc/gdm/PreSession/Default as you suggested but there is not much change.
This is especially noticeable during the "cold" boot. Xspash exits early every time for me in that case (I am attaching a poor resolution video of the login, taken with my phone). You can see that the desktop doesn't show until several seconds after the xsplash exits.
Sometimes, on a "warm" login (if I logout and back in) it will work fine and sometimes it will exit abruptly without fading out or waiting for the desktop to be ready (that's a different bug I think).