We have reviewed your report and are not aware of any issue with the spawn rate of Shukirukin. By design, this NPC will spawn on a random basis and sometimes, have a much lower chance to appear.
If you think improvements could be made to the mechanics behind this NPC, we encourage you to post your comments on the forums, where our Community Team gathers player feedback so they can suggest game improvements to our development team.
Please let us know if you have any other question.
NCSOFT Support Team