Delimiter between domain and username in jenkins user is sometimes \, sometimes _ Why?
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I'm seeing some odd things with jenkins and sending mail.  For some users mail is sent to DOMAIN_username@company.com - some are fine.

Both jenkins and svn are using the same AD for authentication - most users haven't actually logged into jenkins, the username comes from svn. 

the best place to see it is in the `http://jenkins/job/job-name/1234/api/json` and look at culprits

    "culprits":[
    {"absoluteUrl":"http://jenkins/user/DOMAIN_asmith","fullName":"DOMAIN_asmith"},
    {"absoluteUrl":"http://jenkins/user/DOMAIN_bobama","fullName":"DOMAIN\\bobama"}
    ]
Things are goign to work fine for bobama, but note asmith - the email will go to DOMAIN_asmith@company.com (which won't deliver)

If I look at the users configuration page `http://jenkins/user/DOMAIN_asmith/configure`

I see his email is actually listed as DOMAIN_asmith@company.com, bobama looks fine.

These values aren't coming from the user (neither has ever logged in to jenkins) - they're coming from AD by way of SVN.
I'm stuck - anyone point me in a better direction?