Howdy, all!
I'm George, one of the developers working on Jetpack. Really eager to get this resolved, but I can't seem to duplicate it on my end. Is there any chance that any of you could generate a username and password for me to your server, both for FTP and your WordPress Dashboard? I'll try to do any investigating late in the evening tonight to make sure to avoid any visible downtime to your users.
If you could, please email them to georgestephanis at automattic.com -- thanks!