It looks like you changed Abaddon's animation to work with the Brinebred Cavalier's custom horse mount, which is the only mount that has no lead for Abaddon to hold.

Abaddon has 15 mounts (including the default mount). The old animations fit 11 of the 15 mounts, because 11 mounts use horse leads.

3 of the 15 mounts neither work with the old, nor with the new animations.

The new animations only fit for one horse, which is the Brinebred Cavalier horse.

Give him the old animations back, and make him use the nw ones only for Brinebred Cavalier.