Welcome to the world of roach-based horse mods. This mod fixes a number of identified horse-related bugs, including the following:

Missing tail;

Missing or half mane shown on next horse spawn after switching from a saddle that covers the neck to one which doesn’t;

Wrong tail shown on next horse spawn after switching from any of the Toussaint saddles to any of the others;

Horse mane displayed incorrectly over the Caparison of Lament saddle.

You can download this mod to fix the issues described above. It is recommended to keep it installed, as it provides active protection against such problems.