The error shows up e. g. in sh(1), which uses the libedit.
	Do a ``set -o vi'' to enable vi style line editing.
	If you search for `ls' in the history, the shell will either
	show all commands that contain a `l', or will beep at you,
	even if there are commands that contain `ls' in the past.

How-To-Repeat: 
	Enter the following commands to get a history.
	# sh
	# set -o vi
	# lll
	# llll

	Now hit the escape key to enter the vi commands, enter
	/llll, to search for the last occurence of the string `llll'
	in the history. Depending on whatever, the shell will show
	you the command `llll', which is correct, or beep at you,
	which is wrong.  Hit the `N'-key to repeat the search, the
	shell might show you `lll', which is wrong, it should beep
	at you instead.