uh yeah. 0.5.7 and redownloading one copy of each of the standard and mac 0.5.7 update now.

Edit: Is there any kind of cache I should get rid of that might make a difference for the continual update downloads? Not that it happens all the time, just every session.

Have you disabled "Share downloaded files"? That's how I check if the update has been downloaded and it might not show the popup if the option is disabled.