setting is sort by date, newest at top. changed it oldest at top and then back. sort was correct. switched to inbox and back to sent. sort was random again. switched to sort by attachment and back to sort by date. sort was correct. switched to inbox and back. random again. rinse and repeat to no avail.
restarted the app (patented microsoft solution). didn’t fix it.
dread contacting apple support cuz they’re so adamantly useless.
vaguely recall reading about database caches that apple uses. that there’s some drastic way of forcing mail.app to rebuild its indexing. does anyone have enlightenment on that?
It’s not so drastic: Select a top-level folder in the sidebar, select Mailbox > Rebuild. Repeat for the other top-level folders. It may help to quit and reopen Mail afterwards.
Incorrect/random sorting of Mail items has been an issue with macOS/OSX for decades. Apple seems to let it slip after several updates.
It has been particularly noticeable if the number of mail items gets too large. I try to manage this by moving iCloud mail to a local Mac folder each year and reducing the size of the Inbox and Sent mailboxes.