Subject shifts in logfile

Hello,

I found that when I checked procmail's log messages in my mailer, the
Subject appeared empty. After editing the log mailbox, I found that the
 Subject: header was shifted 1 space to the right. This happens even
with the simple .procmailrc:

PATH=/usr/local/bin:/bin:/usr/bin
MAILDIR= $HOME/Mail
LOGFILE= $MAILDIR/from

:0:
received

I use procmail v3.13.1.

Did anybody notice a similar behaviour ?

TIA
-- 
Renaud