I didn't see the issue there, and I don't see it here. Miles would often go home and spend the night in his room even on weekdays if he was around or just needed to talk with his parents. Jon would have access to a time bubble, thus allowing him to do the very say thing, but, ironically, faster and more efficient.
Funny enough, I just realized that if this were the case Jon would actually be in the same city as his parents (maybe even just a block or two away), but just at different times. Kind of strengthens the Miles comparison while putting it on a Superman sized level.
Not to be flippant or anything, but the answer is the writer, Bendis, says if it will or won't happen again, and that it happened in the first place. But given how linked they seem to be making Superman and the Legion as pre Johns' wishes since he started to write Superman, I'd say the back and forth from the future isn't a tall ask at all.
I mean, Johns even wrote a story where, by using a flight ring, Lois got in contact with the Legion, and she asked them over for dinner on a Friday night.
This could very easily be Jon, home for the weekend, talking to his parents about what he did that week in the future.
I don't agree with this. That spot probably belongs to the concept of Robin. Dick, Tim, Damian, and Jason have histrionically been on almost every team imaginable in the DCU. From the Outsiders to the Justice League, DC makes sure it has a current or former Robin on the team--sometimes multiple teams.