You must a least make sure the stair is set to display one storey above. But I don't think it will show the arrow going down if I remember correctly. I never liked the look of the standard arrow anyway and use 2D elements for this information. I just use the 3D stair to show the stair treads.
You might want to put your information in your signature as well so we know what OS and version of AC you are using.
Cheers,
Gerald Hoffman
“The simplification of anything is always sensational” GKC
Archicad 4.55 - 27-6000 USA
2019 MacBook Pro-macOS 15.0 (64GB w/ AMD Radeon Pro 5600M GPU)