Hello, please can you consider how to prevent this type of post from happening from your Mastodon bot code?

I would think either delay the Mastodon relay until the post has been through verification, or delete the equivalent post once it's marked and removed as spam on your forums. There is a relevant discussion on post deletion https://superuser.com/questions/1374498/how-does-deleting-a-toot-work-on-mastodon​

Cheers, Nick