Sorry I can't be too specific on this error, but was in a hurry and not sure how/what happened.
So I had a show running on 3.2.00 (pre-alpha) and air 3.2 (whatever the current 3.2 air is

. This is on a system with 2 graphics cards with catalyst 12.5 drivers running as a single (large) desktop.
Show was running fine.
So I went to a remote signagestudio and changed the current screen arragement of the current show which was too large for the current screen resolution as it was designed for a 1080p while the current screen was 720p.
So I set the new screen size to 720 pixels Y in studio, mad a few changes, and uploaded with the "reset stations" box ticked.
So when I went to check the player "live" the new (modified) show was indeed playing but everything in all the screens was "cut off" at the bottom, like if again the studio screen size was a bit too large and the show didn't fit the physical screen(s) size. I knew this wasn't possible as I was sure I had set up the new screen to 720 pixels, like the physical screen size, and the content accordingly.
So I turned the player off and back on and indeed the (same) show now displayed properly.
So my conclusion is that the "update players" option when saving from studio, if there is a screen size change, may not be setting the right "full screen mode" in the player until the player is rebooted. If you want to try to reproduce my problem, try with a 1080p studio screen, play it in a 720p windows desktop (multiple monitors under catalyst 12.5 if you want to match my setup even more), then go to a studio while the show is running, change the screen size to 720, upload with "update player" checked, and see if it changes the "resolution" of the show properly w/o rebooting the player.
BTW I did get a remote snapshot of the show after the studio-save+update and it showed fine in the snapshot. It's like the player setup a "weird" full screen resolution where a small portion of the bottom of the screen(s) was missing but the player thought it was displaying the full content just fine.
As I said, a reboot of the player cleared it all up, but it had been playing fine before the change-of-screen-size-in-studio and only cut-off the bottom of the show afterwards (w/o been rebooted) and kept doing it until rebooted.
Go figure.
win7 64bits embedded, BTW, and also, my desktop screen resolution was a very non-standard 5120x720