Strange behavior with PS1 prompt

[Petrus de Calguarium]

Donald Russell wrote:

> Any ideas/suggestions?

None, except to report the bug.

I have noticed this problem on and off for years and it 
doesn't have anything to do with the PS1 prompt. Try 
entering nothing on the command line, then use the up 
and down arrows, and eventually your prompt will pick 
up some stuff from a previous command, although, if you 
press the backspace, you will see that the input mark 
is as far left as it can go.