Rails 2.3.2 <=> 2.3.4 SMTP: Recipient cannot contain spaces

Did something change within the mailing support in Rails between versions 2.3.2 and 2.3.4?

I have an app running Rails 2.3.2 with the following string as 'sender' for every email I sent out (new user created, forgotton password, that kind of thing) MAIL_FROM = "MyAwesomeWebsite.com <automailer@myawesomewebsite.com>"

This works fine and in all mail programs I have used it displays the 'pretty' MyAwesomeWebsite.com as the sender, with the automailer@... as the address.

Now that I have upgrades to 2.3.4 (or 2.3.5 for that matter) I always get the error: (Net::SMTPSyntaxError) "501 syntax: Recipient cannot contain a space (<\"MyAwesomeWebsite.com\" <automailer@myawesomewebsite.com>)\n"

Anyone got an idea what is causing this? The error talks about recipient, and not sender. Have some order of parameters been swapped sneakily inbetween these 2 rails versions?