No, all tests done were singular with no predecessor or ancestor. Also, the very first *transaction* OrderID = 1 went in as 'Joe Joe Jones'. And it was consistent. *Every* order when in that way. I ran a weeklong beta with about 10 users and got about 30 orders entered and every single one of them was 'first first last'.
As for the session destroy code, I used to have that in there but I replaced it a few days ago with an Empty Cart behavior. The session destroy is a bit too much for my taste. Not only does it kill all the session variables, it also logs you out in doing so. I don't want them to have re-login just because they bought something. So I switched to emptying their cart and letting them stay logged in as long as they want.
Thanks for your help so far on this but I'm still of the opinion that the bug is something is "automagically" concatenating first + last name and then sticking it into the '_session_lastname' variable which is causing the "echo" affect.
Is anyone else seeing this happen on their sites?