Generally, two accounts merge causes the new mail address get wrong openID/username in Ubuntu Single Log on page.
I have two email address registered Launchpad before, then I want to delete one, I choose merge the account by: https://launchpad.net/people/+requestmerge, and then I delete the old email from my account. When using Launchpad login, I can redirect to my openID ~qzhang, but when I need to login "Log in to Ubuntu Single Sign On", by my new email address, it displays:
If you proceed, the following information will be available to Linaro Wiki:
Full name: Spring Zhang
Username: spring-zhang-merged
The username is "spring-zhang-merged", not "qzhang", it causes I can't be authenticated by some projects I joined hosted on Launchpad! Only if I use my old mail to login, it can get the right username and get access
I believe this is a manifestation of the same underlying problem causing bug 644824. When that one is resolved, this should be resolved. I'll leave this separate and open in case we need to take additional steps then.