Walls only connect to one side of a corner stair block.

HOW TO REPRODUCE:

2x Wall block (any type)

3x Stair block (any type)

Place the walls in a corner shape.

Place a stair block in between the walls.

Use the 2 other stairs the make the center stair a corner stair.

If reproduced correctly, the wall should only connect to one side of the corner stair.