Given:

• a user configured with a name containing spaces (i.e. in People > <User> > Your Name) and a valid email address
• hudson.model.User.get("First name Last name").getProperty(hudson.tasks.Mailer.UserProperty).getAddress() is assigned to an env variable
• this variable is used by email-ext to send a configured mail

Then, sending fails because a constructed address is used, containing the name (with spaces).
When I replace the space with a ".", then it can send the mail, because the address is valid.
I expect that the configured email address is used instead of a constructed one.