[Users] When replying, how is the To address chosen?

[Adrian]

Hello all

I'm replying (Reply, not Reply-All) to a message on Google Groups.  The
group has been set up so that replies go to the original poster
(you at there.com in the anonymised example below).  I don't know if
others in the group are having the same problem but my replies always
go to the group.  Relevant headers below

From groupname+bncBDK4NOEDVM at googlegroups.com Fri May 01 09:20:05 2020
Envelope-to: me at here.com
smtp.mailfrom=you at there.com;
       dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=there.com
Sender: groupname at googlegroups.com
From: The Poster <you at there.com>
To: The Group <groupname at googlegroups.com>

So my reply is going to the Sender: and not the From: address

Is this normal behaviour for Claws?  Is it correct, and is it possible
to change it?  i couldn't find any option to.