Email addresses marked as spam keep appearing as good

There are some email senders who I marked as Spam many times, but whose messages keep appearing in my Inbox (Apple Mail). I have set up SpamSieve to automatically delete messages that are colored [Blue][Gray][Purple][Red] and it works well 99% of the time, but there are some senders, whose messages are almost invariably colored Blue, whose messages keep appearing in my Inbox no matter how many times I mark them as Spam. It seems like they’re doing something with their emails that bypass or override SpamSeive’s filters. Has anyone else run across this or know how to fix it?

Do you mean that you have actual blue messages in the inbox or that messages like those that are normally blue are in the inbox?

I mean I have actual blue colored messages in my inbox

That means that SpamSieve is properly identifying the messages as spam; Mail just isn’t moving them. Here are some things to try. It might also help to go back to the standard setup of a single SpamSieve rule.