UA 3851 then UA 2196 at Houston
Seoul → Houston → Raleigh-Durham
Timetable, Houston time
17:54UA 3851 from Seoul at the gate
12:05UA 2196 to Raleigh-Durham leaves the gate
18 h 11 apart on the timetable, overnight
UA 2196 leaves 18 h 11 after UA 3851 arrives on the timetable: more than half a day, so not a connection we count.