Hi Krel,
There is no error, but there are a lot of unintended consequences going on behind the scenes.
Firstly you have to go way back to the early days of Oyster PAYG and a success story for this site. I discovered that Crayford to Alexandra Palace was always a mixed (NR-T) fare. It was possible to travel using only NR services by changing at New Cross and Highbury & Islington, but that didn’t have a fare defined. Then I discovered that NR had a paper ticket fare for the journey which wasn’t valid on the Underground and therefore cheaper. I queried this with TfL and persuaded them to change the default fare to NR only. As a result, fares from SE London to stations between Moorgate and Hadley Wood/Crews Hill were amended to default to NR only.
Fast Forward to the opening of the Elizabeth line and Liverpool Street LU station was joined to Moorgate as one station. This meant that someone arriving at Moorgate could legitimately walk to Liverpool Street and exit there. So the fares to both Liverpool Street LU and Moorgate were combined with the cheapest fare prevailing in each case.
Another issue that causes confusion is that there are two ways to travel between Abbey Wood and Farringdon. One uses the EL while the other is NR. Both are direct trains so there is no way to tell which way the passenger went.