There's your main problem. Your spark is locking at 18 degrees and you're not getting any idle spark corrections... so it's entirely up to your idle air corrections to try to keep your idle stable, that's if your idle air corrections are even kicking in (which I can't tell from your screenshot).
I can't look at your tune file right now but maybe someone else can have a look and try to figure out why you're not transitioning to idle properly.