2.15.052 The members of a UCI WorldTeam may have no link with the members of another UCI WorldTeam, with a UCI ProTeam or with an organiser of a UCI WorldTour event likely to influence the sporting course of events or to be perceived as so doing. In exceptional cases, which do not challenge the integrity of the competition or the sporting fairness, the UCI Management Committee may grant an exception.
I thought there was an issue with Unibet and FDJ compaies as they're owned by the same people (or were going to be). Maybe it's a title sponsor thing.
This from here: https://inrng.com/2024/01/fdj-unibet-merger/