Why is mail from RT3 not marked with charset=utf-8

RT Users
1

for me, mail coming from RT (Version 3.0.1), e.g. AutoReplies are sended in
Unicode (utf-8) but the mail is not marked as such, hence my MUA tries to
display ISO-Latin1 and fails.

Is this a bug or misconfiguration on my side.

Thamks,
Dirk.