Randomly places emails in spam

Ive noticed this before, and didnt think too much about it until I found something I actually wanted. Ive been receiving emails from a website that I follow, and since I get quite a few, and I see them in my Inbox, I didnt realize that some of them are also going to Spam.

Along with that, I havent been able to figure out any way to mark these emails as "Not Spam."

Anne HW about Email - Edison Mail, v1.6.1