Sometimes a 'brute force' troubleshooting approach is needed to isolate the part/element involved.

1. save a copy of the problem performance

2. Turn power OFF then back ON

3. Load a different performance and then load the problem performance

3. document, and post here, the EXACT steps needed to reproduce the problem 

4. test each part one at a time (mute the other two)

5. test each element, one at a time (mute the others), in the part being tested

I can't reproduce the problem on my M8X based on the info given. Tried CFX2 Bright/Almighty/80s layer and various 2nd inversion G chords both with and without Arp Master. CFX2 vel offset was 68 by default but tried 72.

I'll test again if you can provide more detailed info.