That's new GNOME 3.10 for you.
It changed how background is drawn.
Before, it was drawn to root window no matter if it was done with or without compositor.
Same with COMPIZ.

Now, it was moved to compositor which makes background as first layer window above root window. As that, root window is black.
Conky transparency is done by copying root window data beneath - so now it's copying black for it's background.

The only solution is to use 'own_window_type normal', 'own_window_argb_visual true' and 'own_window_argb_value 255'.

It screws imlib2 images though.

Last edit: Krzysztof Duchnowski 2013-11-21