Jan Wildeboer 😷
When spammers don't like you reporting their spam, they will:
- set up a forwarding email address on one of their servers with good DKIM/SPF/DMARC, typically on a domain that will expire soon
- Run a script that spams hundreds of support addresses/web forms with nonsense content using that forwarding address
- Forward all the confirmation receipts to your email address
That stuff is easy to block, but can be quite a nuisance to the affected support teams.
Larvitz 
