new odd behavior

Good afternoon all,

It's been quiet lately, but I suppose that can be a good thing.

I've been trading lots of email lately with a friend, and he recently  
started complaining that when he replies to some of me messages, the  
To: field does not populate.  It turns out, that happens with message I  
send from Balsa (on my desktop) but not with messages I send from  
Thunderbird on my laptop.  (both Linux)  Note in both cases, I'm using  
a "real" email address, there is not alias or forwarding going on.  (I  
recall Reply-To: shows up when I send with a "From:" address but use  
the SMTP server of a domain different from that address (such as this  
message - from sourceforge.net, but actualy sent through gmail.)

He sent me full header dumps of and example of each, and the "bad"  
message has a blank "Reply-To:" header.  If I look in my sent-mail, I  
do see blank Reply-To: headers, although Balsa doesn't actually display  
them when I show All Headers looking at my Sent Box.

I don't think I've recompiled since May, so I don't think it's any  
recent changes to Balsa itself.

Any suggestions or thoughts on explanations?

Jack