When this was raised shortly after Comp Rework we discussed that we'd try not to add any/more exceptions to how benefits from capes worked regarding the Comp cape - which is why this hasn't been changed since.
However, I've just now made a feedback job to look into this and see what changes we can make. I can't tell you right now what those changes are or when it'll come, however. if you have any suggestions other than "only apply when wearing the Ardougne Cape" though feel free to reply to this comment :)