Thanks, in that video I see what I'd refer to more of as a warble than a portamento. Is this what you're talking about? If so, there are a couple methods to tackle it.
1. Make sure you're on version 4 at least. There was a bug before this that made the warble worse.
2. Make sure you have the pedal calibrated to your guitar or that you have the guitar tuned to the pedal. There is a calibration menu in the system menu, by default it is set to A440. You can make sure your guitar is tuned to this by using the tuner in the Pitch Factor. This warble is really the pitch detector getting confused about which note is being played, and the guitar and pedal being tuned differently can exacerbate this.
3. Make sure you're getting enough level into the pedal. We've made accommodations for a variety of levels, but the pitch detector is really happiest when it get's a loud clear signal. If possible consider driving it with a clean rather than distorted sound as well.
4. If you really want the cleanest octave up sound consider using the harmodulator or pitch flex algorithms. These algorithms don't do any diatonic pitch detecting at all and therefore respond a bit faster.
Alternatively if you're really talking about portamento, I'm not able to reproduce what you're talking about here, and I'm not really seeing it in that video. The one thing the shifters do have a tendency to do is eat pick or hammer attacks so you get a slightly smoother signal which may sound a bit like it's gliding between pitches, but it's not really gliding any slower than your guitar.