I've rebuilt my mailbox - no change. Checked iCloud acc't online - same.I've had random emails evaporate from my iCloud acc't. (iOS iPad 16.2 and Mac mini Monterey OS 12.6) I see the notification, click on Mail, and poof! Tough to know which ones you're missing as you probably just glance at the notification. I was expecting a reply to a specific email and "thought" it was that one. Yup. Confirmed it w/ an email from a separate account. Various places suggest Rebuilding the mailbox. Haven't tried it yet but am mulling. Always afraid that somehow emails will be lost.