Upside down stairs should cut redstone from its back side

Upside down stairs have one side that is the same size as a full block which should stop redstone passing through that side of it and the bottom of it from connecting. 

And this should also give the ability to take a signal from the top Redstone dust, and thereby prevent the feature of Redstone being redirected having a workaround using stairs. As seen in the image below the repeater behind the yellow concrete would usually not be powered but changed. in the middle Redstone the repeater should be able to pull signal from the backside of the stair, but as seen on the other stair it cant pull signal through the block.

How to reproduce:
Launch any version of the game and build the contraptions in the images.

Observed Result:
Stairs dont work as full blocks and dont cut Redstone from the backside.

Expected Result:
Stairs should work as full blocks from the full textured Sides and work like slabs from the not fully textured sides.
It would maybe be helpfull to give Stairs its kinda own mechanic here, with the '1.21 redstone update', where it functions as both at once. (Where the full texture sides work as full blocks, while the non-full-block sides work as half slabs).