If you receive in-app notifications which lead to 404 pages or threads that don't contain new messages, it is also likely that they have been cleaned up.
Unfortunately, it is currently very difficult to also remove the notifications when deleting spam users.
We apologize for the inconvenience.
Hint: If "security researchers" or "computer experts" link to an http-only website, you can almost always consider it a scam.
EDIT FOR CLARITY: The spammer is impersonating a researcher to smear them.
@Codeberg I went to the mentioned website in the spam and apparently a similar attack happened a few weeks ago on GitHub impersonating the same guy who had nothing to do with the spam. 🤨 https://www.bleepingcomputer.com/news/security/github-projects-targeted-with-malicious-commits-to-frame-researcher/