If email recipient's name contains non-us-ascii characters, the name is encoded but it contains extra quotation marks around the name.
Example from the source of email sent from MaxBulk Mailer:
To: =?utf-8?Q? "=D0=90=D1=80=D1=86=D0=B8_B=C3=B6nim=C3=A4=C2=B2" ?= <****@gmail.com>
This will cause...