A forum in French had this photo included. The poster claims that it's the bent lacings of an MDT 178 that bent during a load test. If you look at this post and one at the bottom of the same page, the consensus seems to be that Potain is asserting that the lacings were damaged during handling and exposed by the load test. The point being that the load test itself was not the root cause. Since this happened, Potain has shortened the flattened section in what appears to be an attempt to not have such a long flattened area that would be subject to damage from lateral impacts, or loading, during shipment.
I don't know any of these details to be factual. They do make sense and I think that they are worth talking about and noting for those operating or inspecting the flat top Potains. The jibs are tall and narrow. Given the large flattened area, looking for deformation or any markings indicating a strike in this area would seem prudent.