Like many Super Art voices, it's designed to work that way.
To get the best out of these voices, you'll have to practise! You need to be able to develop a slight non-legato touch. That means that you're not playing totally smoothly, but with a tiny gap between the notes. For other sounds you need to play with a true legato feel - no gaps and no overlapping notes.
I build this into students' playing techniques from Day #1. Some teachers don't do this, and for those who teach themselves, it's easy to get into an overly legato touch. (And equally easy to get into a very non-legato touch!)
Definitely worth spending some time on, as the extra realism that the voices develop is very noticeable.