Any update on this one, as we have just seen the same thing on a LSI MegaRaid controller.

It took a couple of reboots (after the pv resize) just to get the new size to report correctly in Unit size, but as above posts, free space is still incorrect. I have submitted logs to support anyway (Ticket#1010974), this post is just say it's not a 3ware etc. Raid controller-specifc issue. Cheers.