GlassEye
Adventurer
Core Rulebook said:Mounted Movement: A mount bearing a rider can move at a hustle. The damage it takes when doing so, however, is lethal damage, not nonlethal damage. The creature can also be ridden in a forced march, but its Constitution checks automatically fail, and the damage it takes is lethal damage. Mounts also become fatigued when they take any damage from hustling or forced marches.
Does the above quote apply to the quasi-real mount created with the Phantom Steed spell?