I’m using the public beta for OS14, and as per instructions set up my Mac in drone configuration, training using TrainGood and TrainSpam folders in each account. It worked like a dream for the first few days, but now virtually all emails, good and spam, are going into the Spam folders in each account.
My Rules contain Remote Training, Move If SpamSieve Spam and SpamSieve, and I’ve tried different combos of checking and unchecking without luck.
As macOS Sonoma does not support Mail plug-ins, the SpamSieve rule will move every message to Junk without consulting SpamSieve. For more information about the Sonoma beta, please see this thread.