Please click this link to enable some SpamSieve debug logging. After relaunching Mail and SpamSieve, try training one of the good messages as good and one of the spam messages as spam. Then send me a diagnostic report.
It looks like you have two old esoteric preferences enabled that change the way SpamSieve asks Mail to move the messages. I don’t think these are necessary for you now that you are using macOS 10.14. You can disable them by clicking these twolinks.