Hi,
First, I don't know if this issue is really metacity related. Feel free to
correct me.
Oh, and I'm not English native, so sorry for the mistakes.

I have two monitors. I'm using RandR (with Nouveau driver for my NVidia card),
but this bug also occurs with Xinerama (and NVidia's proprietary driver I used
before).
When I open a window which was maximised the last time I used it (Iceweasel,
for example), it first appears on the monitor where my cursor is. But once it's
loaded, it moves on my main monitor (my laptop's one).

The window should stay on the monitor where my cursor is.
Well, it's not so annoying, I just have to move it back. But a bug is a bug. :)
Note that everything's ok with non-maximised windows.

I don't remember well when this issue first occured. But I know it was last
year.

Best regards.