Looks like someone asked a while back whether you've tried unplugging the light chaser board, but I can't tell from your reply if you tried it. I had a flickering digit issue on my Black Hole. Issue went away when I unplugged the light chaser board, and I was able to fix it by adding a ground wired to the light chaser board. When you did your ground mods, did you add a ground to the light chaser board?