[awegio]

That's probably because you confused Vim and Kakoune key bindings.

Kakoune

- n: next match

- alt+n: previous match

- shift+movement: extend selection by movement

Vim

- n: next

- shift+N: previous match

So if you press shift+N as you are used from vim, you start adding a lot of selections instead of going to previous match. I believe this difference is the most confusing for people who switch from Vim to Kakoune.