Touché (SE)'s mechanism is extremely sensitive. Therefore it is normal behaviour that Touché (SE) might send some values from time to time, even when you don't touch it. In these cases. it might react to subtle vibrations of the surface it is placed on. This is especially true for the lateral sensors (left and right).
If the MIDI messages are causing a problem in your setup, the most convenient way to prevent Touché (SE) from sending MIDI altogether is to switch your Touché (SE) to Freeze Mode via pressing the Encoder once. Touché (SE)'s LEDs will pulsate to indicate it is frozen. You can unfreeze the unit by pressing the Encoder again.
Of course you will also have less of these random MIDI messages when you decrease the sensitivity of your device as described in this article: Adjusting the mechanism's sensitivity