For a mistake, I agree with you.No I have not missed it. But I think you have both missed my point. I did agree the AR (junior or not) is wrong.
Your game management skills is more than just managing players and the bench. It includes your AR's and in my opinion the way @GraemeS has responded to a mistake form an AR is very wrong and can only lead to further no good things. There are better ways of handling it.
Edit: the examples I used don't necessarily need recording. But that's beside the point.
But if we ever found ourselves in this position, I will have given explicit pre-match instructions to the AR to be the eyes and ears. So this isn't someone who is having a bit of a non-focused moment, it's someone who not only has consciously choosen to ignore pre-match instructions, but is self-centered enough not to realise how wrong they are by insisting I take a break from my game to reinforce their incorrect actions.
They need to clearly and firmly be reminded that they've been given instructions and need to follow them. And if it happens again, I'll absolutely be giving up on doing so politely.