Hi Bof bof,
That's strange indeed.
If you set the Portamento-Glissando rocker switch to Glissando while keeping the Portamento-Glissando white slider to short, do you get stepwise variations or is it still smooth?
To help locating the source of the problem, you could try and probe at K4 (just behind the buffer) on the KAS board while playing. If the pitch signal there varies in time, the problem would most certainly be on the KAS.
Joachim