Zebra Formant Filter problem @96 khz: clipped/distorted sound

[spinlud]

Hi!

I found a strange thing, if i use in zebra-2 or in zebrify the vfc filter in formant mode (and increase a little the formnt knob) i got completely clipped and distorted sound if the sampling rate of the project is 96 khz.
If the project is running at 44.1 khz i got a normal sound, without clip and distortion. I've verified this thing both on cubase 7 and ableton 9.
I have to say that the problem is happening with formant mode only, other modes of filter work fine @96 khz.

Anyone else is experiencing the same thing? Any fix for this?

Thanks in advance for any help!