Placing wooden stairs (minecraft:oak_stairs) or Cobblestone stairs (minecraft:stone_stairs) after installing 15w35b, makes them invisible (the client does not know they are there) for other players, and for yourself when you log out and back in again. It does not matter in which rotation you place these stairs. This also happens with the /setblock and /fill command.

However, wooden / cobblestone stairs which already were present in a world before 15w35b DO appear correctly

Tested this with every stairs in the game, and only the oak wooden and cobblestone stairs show this behavior