What exactly is a "short chair" supposed to be? Especially as opposed to a small chair?
Definitely a bad translation. Chairs are small, not short. Report it!
Chairs are not referred to as short, even if they are so. They can be low-backed or high-backed. A highchair means something else, of course. They can be large or small. I don't think that a short-backed chair is necessarily a small chair.