[MM3-users] Text encoding problem, preapproved header

Mailman 3.2. I send a message to the list with some national characters (æøå ÆØÅ), and everything shows up fine. Then I send the same message using pseudo-header approved: with the list password. This messes up the character encoding, so that instead I get (=C3=A6=C3=B8=C3=A5 =C3= =86=C3=98=C3=85)

I experience the problem when I send or receive with Gmail web client, however, when using the Claws-mail (an ordinary mail client) to pick up from my gmail account, the contents is shown correctly.

Any suggestions?