There’s a pretty reliable 2 week or so delay between any given event and changes in the approval rating. However weird or unreliable individual tracking polls are. That sort of thing is really well established.
That said Trump’s approval rating has been bizarrely stable for about 6 months. He’s been cycling around ~40% since January. Up from a previous, more volitile period where he bounced around the 30s a lot. But hes within a few point/margin of error of that now. And there he’s stayed. Its a bit weird. His approvals are bad. But they just seem to be staying exactly as bad, regardless of what’s going on.
But the most recently released polls cover the previous week/5 days. So tail end of his Korea “victory” and the very early start of the fight over child detention. The Korea stuff would theoretically drive him up a bit. You’d expect to see impact from the child detention story starting in the next release of polls early next week. Then the full impact the week after. Depending on how long it remains the major issue in popular discussion.