I confirm on version 15w42a
Confirmed for 15w42a
I have found this glitch but it seems that as long as you are walking into a wall next to the stair and there is a block that is two blocks up and to the right then you will have that issue on the right of that stair if there is a block two up and one to the left then you will have that issue on the left.
I can also confirm on version 15w41b but not 15w40b, and can't test 15w40a.