First, how do you know the email is not going to that person/address? Have they told you that? Does that address show when you view the message in your "Sent" mailbox?
I know these sound like silly questions but I'm really
not saying you don't know what's happening.
It's simply that a few weeks ago my wife asked me a similar question about a group she wanted to email. She said, "Look! I have these x number of people in this group but these don't show up in the 'To:' field!" I must say, I did not realize what the real problem was for some time. Like you, I double-checked that the people were listed in the Group. I opened new email windows and saw the same thing happen to me!
I finally realized that the cause of "problem" was staring at me on the right-hand edge of that "To:" field.
It was a scroll bar! Mail was "trying" to tell me (and my wife) that there was not enough space in the "To:" (or the "CC:" or "BCC:") field to show all the addresses I had entered. At least if they had been entered 'automatically'. I think if they are entered manually, you would probably notice the first line of addresses sliding up, under the top of the field. Perhaps the devs never thought about what happens when using Groups?
Anyway, that 'fixed' my wife's '
missing addressees' problem, I hope that's all you are seeing and it will fix yours!
It probably doesn't help that Apple decided to make these scroll bar areas so narrow!
