https://api.transitous.org/?tripId=20251217_21%3A44_de-DELFI_3060997859
and
https://api.transitous.org/?tripId=20251217_21%3A44_de-VBN_472481302
are the same train, but with different real-time information (although they differ only by one minute at most at the time of writing).
You can't find them by searching for a route, you have to click on the map markers.