Never seen this one. New myth using myth starter bundle, all worked well with combat and mounts. Stitched starter bundle to Aquilan armor kit from packs.
1. entering combat with a street mob, mount disappears, but wizard is still floating face down a body height above the floor, it adjusts slightly during 1st spell cast: character is inside/outside the circle and floating approx a body height above floor. It may correct after a few rounds. 2. using a broom mount, character floats a body width above broom.
There are multiple variations of the above. This is the only wizard with the problem, all others are fine.