I've figured out the problem recently. When you mirror an archistair object to change the direction of rising, the stair disappears. But if you leave the direction by defaults it works properly!
I don't know any other way to make a stair rise in CCW direction except mirror it
I haven't try 1.10, but I know that 1.9 has the same problems. Could anyone who has Archistair 1.10 make an experiment with U-shaped stair, please