Wouldn’t it cause some sort of force locally at the atomic level all the same even for tightly coupled systems? They shouldn’t feel the expansion as it is not a force from my understanding but just growth of space itself. But for example wouldn’t the orbit around an atom be off just so slightly that it would need to expend some level of energy to correct for lack of better word.
Or do we think this does happen but the amount is so small that we can not measure it experimentally in any way.