Digitech RP255 volume pedal-problem?

[Jonathan Neher]

Hi,

I just got a Digitech RP255 to use as a volume
pedal, EQ, delay, reverb. I'm not using
any of the amp models and I'm getting a great sound
out of it. The only problem is that
when I strike a string and try to swell it
with the volume pedal, there is a scratchy
sound at the beginning of the pedal throw.
As soon as you get past that spot at the very
beginning of the swell (where it starts at
nothing and then the sound comes in) everything
is great. It sounds like a dirty pot
or digital artifact. I don't even know whether
they use a pot as an encoder or not.

Has anyone else (who uses an RP250, 255, or 355
had this problem?

Thanks,

Jon