Reproducible encoding problem

Hello,

Here is a problem, which I can reproduce:

EmailOutputEncoding is ISO-8859-1

User “lueck” with email "lueck@mi.fu-berlin.de" and Realname “Sebastian
Lück” produces in From-headers originated by RT 3.0.2pre6:

From:
=?ISO-8859-1?B?IlJUL01JIChTZWJhc3RpYW4gTPxjaykiIDxydC50ZXN0QHRlYy5taS5mdS1i
ZXJsaW4uZGU+?=@tec.mi.fu-berlin.de

The ISO-encoded string should not span the first part of the emailadress.
At most two MUAs I use (Mulberry, mutt) cannot decode this, and I think -
but I am not sure - it is illegal.

Dirk.