There is a lag between different values of pitch bend, like portamento. I've seen that in other synths also but here it is more pronounced. Is this a choice?
I have a little module in Reaktor to tune equal tempered synths that instead of midi note numbers it sends pitch bend values. That's how I noticed it.
It is intentional. Many controllers send out a low-resolution signal for pitch bend, with only 128 values. If the pitch bend is not smoothed on the way to the synth, there is always a clicking noise when moving the controller.
I'll have a listen and see if I can make it faster.