Apple Mail not showing the preview of the selected email in local mailboxes
I've seen this issue with older OS's as well but I'm running 12.1 Monterey on an Apple Silicon MBP running Mail version 15 and I'm experiencing it here. This only applies to local mailboxes you create and are stored on your hard drive/SSD. I use the old Classic View in Mail which puts the mail list at the top of the screen, a separator bar below it and the Preview of the email at the bottom. However, this issue exists no matter which View I choose.
When working correctly, you single click to select or highlight the email you want with your arrow keys and the Preview Pane then displays the email. If you simply use your up/down arrow keys you can rapidly select any email in the list and the Preview Pane quickly displays that email without having to open that email via a double click. Works great when quickly trying to find a certain email.
However, in many, but not all, local mailboxes, when I select an email in the top list, the Preview Pane seems to be stuck on another email and no matter which email I select, it will only display the one it wants and will not change as I move up and down the email list with the arrow key or mouse. Normally, it likes to stay on the first or second or last email. If I double click to open the email, that works fine and I can read that email but once I close that email and go back to the email list, the issue is still there.
Apple support suggested I reload the OS which I did but it didn't help. They also suggested I reboot without having WiFi or Ethernet connected, that didn't work either and they had me rebuild the local mailbox which only works the first time I try selecting an email but once that email is successfully selected and displayed in the Preview Pane, it won't work correctly after that.
Any ideas?
MacBook Pro, OS X 10.11