This requires a bit of context, so I'll try to explain it to the best of my ability.

• User A is an active member of my sub, a pretty nice guy if you ask me.
• User B is, as far as I can tell, a troll account:
  • They have only posted to the sub once, and commented twice.
    • The post was a plain text post, no body, the title was along the lines of "Fuck User A" with no explanation why.
    • The first comment was under a post made by User A, essentially saying "Fuck you." I removed it. Then, he replied to my removal message three days later simply saying "Fuck you"
  • It's probably important to mentioned that their usernames are strangely similar. Not exactly the same, but similar.

BUT! Whenever I go to User B's profile page, or view anything about the user, it gives a 404. Even through the API, it gives a 404. At first, I just thought that they made the account, posted that, then deactivated it, but then they commented again, so that can't be the case.

What should I do? Is this a bug? Or is there a setting where it doesn't let you view their profile page? Should I contact User A about the situation? Should I perma-ban User B? I'm not very experienced in moderation, so I don't know what I should do.