Apple Mail smart-mailboxes not working [consistently]
(This is similar, though opposite from, Apple Mail mailboxes not working after new 10.13.4 update)
I have a "Smart Mailbox" for "Unread" mail - which is defined as:
In the past, if I click on some random mailbox and then click on the "Unread" mailbox, all previously read messages would have been removed from the header listing for the "Unread" mailbox.
Recently (possibly as of the update to 10.13.4, possibly earlier) I've started to notice that messages that have been read still show up in the Smart Mailbox - despite no longer being "unread" (no 'blue-dot' icon in header), and having clicked back and forth between various mailboxes.
If I Rebuild the various mailboxes that "feed" the Smart Mailbox, the read messages from those mailboxes will get removed from the "Unread" list - Rebuilding the Smart Mailbox itself has no effect.
While this is not a catastrophic problem, it is annoying.
Is there something I can do to fix this so that read messages are once again removed from the "Unread" Smart Mailbox when the view is refreshed (clicking on another mailbox and then clicking on "Unread", quitting/restarting Mail, etc.)? Or is this a bug that needs to be fixed on Apple's end?
Thanks,
--fish
MacBook Air, macOS High Sierra (10.13.4)