This is definitely a Kermit problem... (Off-Topic)

by Claude Errera , Thursday, June 22, 2017, 14:54 (2712 days ago) @ Kermit

Your mailbox is full a lot of the time, and your ISP bounces mail IMMEDIATELY when it is. As someone who runs a bunch of automated email systems (like the one that sends you mail from Kickstarter), I know that for the most part, these failures are invisible to the sender, because it takes work to notice them, and most of us don't do that work. (If you send someone mail from a personal account, and it fails, you get the failure message back into the same account as you sent from, and you almost always see it. If you send someone mail automatically, and it fails, the failure message goes to a specific place - one that's usually full of all SORTS of failure messages, not all related to email. Unless someone is being diligent about checking, it's possible that these messages are never even noticed.)

I would bet 5 donuts that each of the missing updates were sent at a time when your box was full, and they simply bounced.