I hope I'm not the only one thinking the below is weird and even somewhat disturbing:
Yes. The "New contributor" indicator that ask us to welcome the user showing on a spam post.
I believe there's no need to explain why we better not welcome spammers/abusers to Stack Exchange, so here is what I suggest to do: if a user has a post marked as spam/offensive and approved as such (6 red flags or single binding moderator flag) do not show the New Contributor indicator for that user.
Another alternative is post based: since the indicator is showing based on post trigger it might be even more simple, if the post is marked as spam/offensive (same criteria as showing the "This answer was marked as spam..." message) then remove/ignore the "new user" trigger for that post. This will show it for other posts made by same user, but still better than showing it on obvious spam posts as it is doing now.
Worth also to mention, it's not only for "us", but also to prevent the spammers/abusers themselves feeling welcome. If someone who posted a vulgar/abusive post will see that card when viewing their own (deleted, but it's not really relevant) post, they will feel as if they can just do it again.