I will just quickly jump into this debate.
When I was in Veselay in January 2020, I remember asking a helpful, English-speaking woman at the Veselay tourist info office about this second location at Corbigny. But I do not even remember what she told me, probably because it was nothing significant. Since she was so helpful, I just called her a few days ago, asked her the same question again and even had her download the WHS map and look at it.
Although she did not even know that the area was referred to as "Corbigny," she mentioned that there was an old "cross" (47°27'24.9"N 3°44'14.6"E), which I believe Solivagant briefly mentions above. It is this cross that created the second location, I would love to say, but I do not think that is the case. The woman said that the cross has probably something more to do with the Route of Santiago WHS.
I think the best view of Veseslay from the second location can be had at the grilled gate (47°27'25.2"N 3°44'10.5"E) on Google Street View. You still need to zoom in.
From the WHS map the first location of this WHS looks somewhat triangular, and I would say asking why this second location is included is like asking why the south-east corner of this first (triangular) location is included. They all probably just offer nice views of the Veselay village, as it is also one of the "Les Plus Beaux Villages de France," which pikkle and I talked about on top of this page. So at this point, I would say, forget about "why" and just enjoy this beautiful village from any angle.
After writing the above, I just tried a different approach and might have come up with something interesting. I just downloaded the huge PDF map of the Routes of Santiago de Compostela in France WHS and looked at the Veselay section of it. 8 pages are devoted to Veselay. On page 204 there are two maps and the one on left is intriguing!
What is that pink circle (with 500 m radius) placed right over the second location of the Veselay WHS??? At the top left corner of this map it seems to say the pink represents "protection perimeter of a historical monument."
Below is the Google translation of what it says under this map:
"The Sainte-Madeleine basilica is owned by the municipality of Vézelay.
It is protected by an inscription on the list of historical monuments of 1840, confirmed by the Official Journal of April 18, 1914 (cf. Minutes of the permanent delegation of the Higher Commission of historical monuments of March 25, 1968).
It therefore benefits from a perimeter of protection of its surroundings with a radius of 500 m and is located within the perimeters of protection of seven other buildings and land protected as historical monuments in the municipality of Vézelay.
On the other hand, the city has a protected sector since December 23, 1993 (with an area of 33.44 ha) whose protection and enhancement plan (PSMV) has been approved since 2008.
In addition, the Sainte-Madeleine basilica, the municipality of Vézelay and the neighboring municipalities are part of a vast site classified since December 9, 1998 with an area of 10,355 ha."
It is not easy for me to understand it with this Google translation, but it seems to say "these areas have been protected since 1840"??? Is it possible that some significant historical monument was there at the second location back in early 19th century?
Can it be that "cross"? :))) I mean the cross is located right at the center of this pink circle!