I was just demoing Jupiter 8v and noticed the same clicking on most presets. It's not on first note/chord, but appears when playing a sequence. I think it's some strange ADSR thing, because I got rid of the click on some presets by tweaking VCF ADSR. It's not as simple as attack or release being too quick tho, it's a combination of many parameters.
I'm not sure if it's supposed to be this way, but the synth engine seems quite unpredictable when it comes to playing consecutive notes in other ways too.
This behaviour is propably a decision maker for me, it's a big turn off..