瑜伽論記 18.129

18.129

異作異受者，此所計我若念念無常，即此身我能作業而不受報，餘身之我受其果報而不作業。

As for "different [agents] acting and different [agents] experiencing": if this imputed self were impermanent from moment to moment, then the self of this body could perform actions but not experience retribution, while the self of another body would experience its karmic retribution without having performed the actions.