When selecting and deselecting chords in the Main Track, velocity of an individual chord would be reduced. When selecting another chord, the previous velocity would reset and the newly selected chord would experience reduced velocity. This velocity change was not visible in the midi window and was not affected by changing velocity in that window. It was visible in the Main Track chord display and was audible on playback.
Mac Studio M2 Sonoma Ableton Live 12.1 using VST3