Communication is truly awful isn't it. Saying that, I don't think I'm signed up to the newsletter, which might help. I accidentally signed up to it when I accidentally created another account, so I know it exists. Took me 3 months to notice I had a 2nd account with a handful of followers on it.
The fact they didn't notify the entrants directly of the winners is just shit.
The notifications - we don't get them all. One day you'll probably find a comment on an old story that you were never notified of, and end up apologising to the person. It happens a lot on long conversations.
The disappearing comments - I think once the comments get over a certain number, medium selects a random selection to show. They don't show them all. I've seen my comments disappear from a feed, but then they're clearly there later.
Good list!