Hi @KrimsonKiller I'm sorry to hear that the NPC 'Sleekit' has not spawned. Is it possible that you visited that area previously and killed the NPC without looting the key?
Could you please provide a video that demonstrates this issue.
I would recommend uploading your video to a video sharing platform such as YouTube, you can then copy the URL link into this thread.
Can you also ensure that your latest save is uploaded to the cloud. If you are unsure how to do this there is a support article that you can check here.