Razing a Town is supposed to make the land unsettlable. Not a bug. Keep in mind there is a Warhorse and Horse. Warhorse is available when you have the horse resource connected to a town.
Odd, many time before, I can buy horse for my hero before in shop after reseaching even there is no resource, other thing reseach said .25 rate horse grow,
but in this case, not anymore, I'm playing customized race with customized Sovereign, for the first time in many game from war of magic and this game, it's Amarians (customized, just using amarian as my custom race) due to bloodline bouns. I used to playing as Altar as my custom race almost all the time till .90 of this beta game. 10% of exp don't seem much in long term when amarians bouns seem good if you had control lot shead but it's rare last of my game play oh well,
I used to play as custom altar and always had a horse in shop after I done reseaching horse and did proved me .25 rateing but now I don't had horse and no .25 rate even reseaching tech said that tech tree in this .90.