Maybe I should have called this simply Activity. I stand corrected, I should have called it the audio from the MIDI activity, the sound exported from the instrument.
Are you getting activity in the meters when a track is muted?
If I mute the track from the Track List, both the audio return from the instrument as well as the MIDI going to it will get muted and I see no activity in any meters.
If I mute the instrument’s audio return channel in the Mix Console, I get the same result as in example 1 above unless the instrument has had additional outputs enabled.
If the instrument has had additional outputs enabled, the Mute button in the Track List will only mute the MIDI and the Mute button in the Mix Console will only mute the audio return channels.