Duplicate Scrobbles with iTunes Match

Here's my setup:

2 Macs on OS X Lion
iTunes 10.5.1 on both
Last.fm Client 1.5.4.28012 on both macs
Libraries synced with iTunes Match (play counts and last played info is automatically synced)

I think what's happening is I'm playing an album on Mac 1 and it's scrobbling with the last.fm client as it's playing. Then, when I get home from work, I log in to my other Mac and see pending scrobbles. These scrobbles are the same ones that I scrobbled while at work.

iTunes match updates the play counts in both iTunes libraries and I think the last.fm client is not smart enough to realize that it already submitted them.

Is anyone else seeing these issues?

Thanks!

All of a sudden tracks that I play on Itunes appear as 2 tracks, and count as 2 tracks in the artists' library. If I try to erase one of the tracks, they both get deleted. What could cause this and how can it be fixed? Anyone know?

yeah i've been having problems with this for ages

after i update my ipod it re-scrobbles all the music I've been listening to on my macbook, since my last ipod dock.