I contacted support but also wanted to post something here in case it helped: for some reason, certain rack effects and pedals seem to have knobs that won't turn in both directions using the interface. The Sat-X saturation rackmount and Phazer 10 are two examples (the Phazer-10 had the same issue for me in Amplitube 4). Interestingly, you can do a workaround by assigning a MIDI controller like an expression pedal to the knob, but that's not superconvenient.
If this isn't a great place for mentioning this, my apologies. I just thought I'd mention it here to see if anyone else had the same issue and to draw attention to a very minor inconvenience, not a showstopper bug, on a very good product.