I was forwarding something to my wife and I see this other person suggested in the recipient list. The weird way the suggestion UI is designed makes it look like they are already added, but I assumed I would have to select the person in the second forward box to add them. Anyway, I won't migrate for now though because I hardly use email anymore.
Same issue here. I want to migrate away, but rarely use email and I have it setup everywhere which would take quite some effort to pull off.