lines splitting on saving

Recently (only noticed it today) I find saved messages
(saved with 's' command) are saved with long lines split.
An equal sign at end ("=") and often "3D" the hex code
for equals at the beginning of the next line.

My .muttrc has the following, unchanged, set of lines:

# 
set wrap=0
set reflow_text=no
set reflow_wrap=0
set text_flowed=yes
set smart_wrap=no
#

Any explanation for this new behavior and possible fix?

-- 
Jon H. LaBadie                 [email protected]
  154 Milkweed Dr                 (540) 868-8052 (H)
  Lake Frederick, VA 22630        (703) 935-6720 (M)