Same thing happened to me. Didn't know your hack so I restarted my mac!
Tell me, would it be a stupid idea if the user could tell KM that a precisely determined conflict should be canceled?
So in this case ⌥+a opens the palette. If the palette is already open and ⌥+a is pressed again, then don't generate a conflict but run the macro.
Some kind of order how conflicts should be solved. If the user wants that.