update: the tunnel changes are in and have been verified. We expect the intermittent error pages when viewing your account information to be no more.
Alright - we've tracked down the intermittent errors (previously mentioned here) to our IPSec configuration that connects our various data centers together. We have worked out an improved configuration, tested it in the lab, and will implement it tonight.
Customers should not expect an interruption in service outside of intermittent errors when viewing the account and user info pages. As soon as our changes are in place, I will update this post and your pain should be no more.
I apologize to any who were affected. This was an unexpected side effect of the upgrade that I performed this weekend, and although it will bring greater stability in the long run, it is unfortunate to have these sorts of problems up front.