I think the difference is the target affected from each attachment. Extra Sharp's effect is on friendly ally (A) not opposing ally (B). So when in combat, A has +2 attack and ALR doesn't "see" any opposing attachment has a direct effect on B.

In th case of Into the Forest, it's the same. Hero is hidden but that affects no allies on the board.

Now with Subdue/Turncoat (and ofc CB, CP, Hymn, etc) the attachment has an action directly affecting your allies. So ALR kicks in and stops all those effects.

In my mind the differentiation is clear, I am not sure if I have explained it well though.