How can I reset the predictive mailbox action in mail on a High Sierra?

Mac Mail's predictive "Move To..." predictions have suddenly stopped working for my incoming email messages across all target (saved) folders. I have moved each incoming mail message to its correct mailbox over and over, and the prediction offered (when offered) remains stuck on one folder (nothing special about that folder, in fact it's not one I ever move a message into explicitly so this is acting like a random choice by Mail).

The point is, Mail is not "learning" the correct suggested/predicted folder from my recent days of 'Move' actions on incoming messages.

This is an old (and oft-asked) question. From past threads please do NOT suggest that I use rules to accomplish this. I do use rules in many cases but those of us who use the predictive move capability have our reasons for wanting this to work. It used to work (a few weeks ago) and now it isn't.

Is there anything that can get the predictive Move feature back working? Thanks