I've had this problem and I've heard from several others about a high enough trader not being able to sell a horse to a trader via the Brokers' Office. And vice versa, a trader not being able to buy from a high enough trader. The clerk says that you aren't high enough to own a horse according to the Traders' Guild, (mentions something about a license) even though the trader customer doesn't own a horse already.

Is this intended or being looked into?

Thanks