Most Helpful Guy
Yes this can be quite annoying... I would recommend bringing it up to him but in a manner that would involve a solution to both sides of the party for example ask him to message you saying whether or not he's busy or perhaps a heads up thats he's going to be busy for a little while.
Most Helpful Girl
I think it is all up to the individual. I personally don't care as I know he is in his own space and is preoccupied by his friends. And the reverse happens when I am out with mine and I don't reply straight away. Just talk with your partner and find out what works for you 😄