iCloud emails suddenly disappeared from Mail inbox on iphone, other folders not affected

Today all the iCloud emails from the past 12 months suddenly disappeared from Mail app on my iPhone 11 (ios14.1) as I was looking at the screen, without doing anything at the time. Older emails from 2019 were still there. Tried upgrading to 14.2 but that didn't work. Checked iCloud emails using the browser on my Mac and they're still there, just not visible on my phone. Moved some of the 'missing' emails to another folder online and they reappeared in the other folder on my phone. Moved them back to inbox online and they vanished off my phone again. Also, when logging on to iCloud in my Mac browser, a password was sent to my phone, which instantly made all the older emails (from 2019 and before) disappear from my phone as I watched them vanish in the background before my eyes. Is this a glitch? Has anyone else had this today? Or has something happened to my phone, which seems unlikely as nothing changed on my phone when all this happened.