We are using version 4.0.8 and replaced user.php according this issue:
http://stackideas.com/forums/fatal-error-users
When you start a user list to see the members you see them all.
Enter a search value. The list is filtert correct.
Clear the search value and hit Enter. The list is still filtert according the previous search value.
This happens in the browser Edge, Firefox and Chrome work fine.