When using MIDI messages to trigger cues/scenes/snippets in the M32, by default, a confirmation pop up will appear as below. 

See the instructions below is you want to turn off the confirmation pop up.

If you are using the console itself, go to the Setup, config screen and unselect Scene Load (under Confirm Pop-Ups) on left side.

If you are using the M32 Edit, go to the Setup, Mixer screen and unselect Scene/Preset Load under Confirm Pop-Ups (Edit) (right side).