Sounds like velocity switching, not legato PLAYING that makes this sound. AFAIK, the regular Wersi engine cannot distinguish legato play from detached.

But legato/marcato vel-switched sample sets have been around for EVER. The problem comes when you want to switch between them AT THE SAME VELOCITY!

Note how every phrase starts fairly loud. That's the player whacking the note a bit harder to bring in the 'bite'. Then the lower velocity sounds are legato samples. It's how everybody did it until GIGA etc., and then SA.