Inconsistent activation redstone

I build a small tower of blocks with pistons next to them but activation seemed off. activating a block should power all objects perpendicular to them... so i thought.

So I build a small test, see image below.
1 layout: with a red stone torch in the center with 8 objects around it (like building an oven)
Horizontally the pistons and lamps act the same, but vertically there is a difference. Notice the difference in top and bottom corners?

Is this working as intended? If yes :dizzy: , why and how does it make sense? If not, hope you can resolve this.
Thanks