Something changed after one of the recent patches and it would seem the old way of adding a new ancillary(mount in this case) to an existing Legendary Lord is no longer working, in my case I have a skill node, auto unlocks at turn 1, it is supposed to grant the mount ancillary, and the ancillary is just the sisters of twilight but without an actual mount, it's just them on foot, and this always worked. and it STILL works in Custom Battle, you can choose none(the on foot version) or the eagle or dragon mount, but in campaign the option is nowhere to be found.
If anyone knows what changed and what must I do, that would be great, the mod is in Steam Workshop and the name is Elves Enhanced and ... lol ... and then you can just download it and see it in RPFM, and ... haha, yeah that's what I meant when I said "features" in the title ...anyway, and then download it and just check the tables, see if you find anything wrong, I doubt it but you never know, and tell me if I'm missing anything that is new that needs to be added for this to work again.