Hello Fabio,
No reset on the AlphaTrack. But its not likely that the problem is actually with the AlphaTrack itself, but rather with the way Nuendo is interpreting its messages.
Here's some things to check.
1. click on the AlphaTrack desktop icon and make sure it is set for 'Native' mode.
2. Check your Device Setup configuration and make sure that you have 1 instance of AlphaTrack and both MIDI ports are set to itself. There should be no other controllers such as Mackie Control assigned unless you actually have one of those devices also connected.
3. Go to Device Setup/MIDI Port Setup and make sure that AlphaTrack is NOT enabled as an "All MIDI" device. Or an MIDI tracks in your project could incorrectly react to AT messages.
4. Try removing the ALphaTrack from the Device Setup and adding it back in again. This might reset Nuendo preferences in case they have become corrupt.
I'm assuming that it was working ok previously and that you have current updates for ALphaTrack and Nuendo3. . Are there any other changes that you have made to your MIDI configuration since that time?
Check these things out and let us know any new details that you can. Also, Mac or PC? OS?
CS