repeated hostname in PS1 in ksh

["Jeremy C. Reed" <reed%reedmedia.net@localhost>]

Many times, almost everytime, for years, my hostname is repeated when 
shown in my PS1 prompt set by .profile in ksh:

sunflowersunflower:reed$ echo $PS1
sunflowersunflower:${PWD##/*/}$
sunflowersunflower:reed$ grep PS1 ~/.profile
PS1=`hostname -s`:'${PWD##/*/}'"$ "
sunflowersunflower:reed$ PS1=`hostname -s`:'${PWD##/*/}'"$ "
sunflower:reed$ ps $$
  PID TTY   STAT    TIME COMMAND
23885 pts/2 Ss   0:00.05 -ksh 

I see this on other NetBSD systems with ksh too.
Anyone seen this?

I will try to track down because I don't think I have ever seen it on my 
3.1 system.