odd email parsing (misparsing?) issue

[Jack <ostroffjh sbcglobal net>]

Background:  Having fixed my link opening issue, I just installed  
notmuch to see if it might help me with searching, since I sometimes  
seem to "lose" messages due to having changed the folder hierarchy and  
how I decide where to put messages about various topics.  However,  
notmuch does not deal with mbox files, and I have several of these, so  
I figured that converting them to maildir would be a good time to go  
through them and purge messages no longer needed or referring to long  
gone web sites.

Problem:  I found at least one mbox file that seemed to put balsa into  
a 100% CPU chewing mode, with the status area in the lower left just  
moving the bar back and forth forever.  By manually editing the mbox  
file, and moving a few messages at a time into a separate file, I  
finally found what I think is the culprit, although I'm sure I've  
looked at this message in the past without problems.  The body of the  
message includes a line that starts with "From " immediately after a  
blank line, and I wonder if balsa is getting confused by thinking this  
should start a new message, but not finding any header lines following  
it?  Changing this line by adding text at the beginning "This is  
From..." let balsa deal with it without any further problem.

What SHOULD happen with such a message?  Should that line be quoted in  
some way?  Should the lack of a header ("^.*: .*$" with perhaps length  
limits on what is before and after the ": " ?) be taken to say this is  
NOT the start of a new message?

Am I chasing irrelevant wild geese?

Thanks for any suggestions.

Jack