UA 3902 then DL 811 at Houston
Cape Town → Houston → Miami
Timetable, Houston time
03:11UA 3902 from Cape Town at the gate
15:25DL 811 to Miami leaves the gate
12 h 14 apart on the timetable
DL 811 leaves 12 h 14 after UA 3902 arrives on the timetable: more than half a day, so not a connection we count.