Incoming Mail not loading all messages in All Inboxes on Mac

Usually All Inboxes loads all incoming Mail. Not lately. Due to pilot error (creation of Smart Mailbox) Incoming Mail shows a few random msgs (5 at present) going back to '13.

All my account Inboxes show "Primary" first. That's new.

Advice appreciated!

[Re-Titled by Moderator]

Original Title: Incoming Mail kaput.