How to make "Train as Good" stick?

OS10.15.2, SS 2.3.9 - Mail from sources trained as “Train as Good” for a considerable length of time/number of sources keep appearing in Bulk rather than InBox. How to make “Train as Good” stick?

The Train as Good command tells SpamSieve that the message is good, so that it won’t move future messages like that to the Spam mailbox.

SpamSieve does not move messages to the Bulk mailbox; rather, that typically happens because of a junk filter on your mail server. You may be able to turn off the server filter or configure SpamSieve to rescue good messages from the Bulk mailbox.