瑜伽師地論略纂 5.50

5.50

修生生差別中有四：一、生因；二、染退善進；三、修因處；四、辨差別。　「既生彼已，若起愛味，即便退沒」者，非上地中定可有退，由多愛味，損減壽命，名便退沒。此退生也。

Regarding differences in birth resulting from cultivation, there are four points: 1. the cause of birth; 2. falling back due to defilement and advancing through wholesome states; 3. the locus of the cause of cultivation; 4. distinguishing differences. Regarding "Having been born there, if one gives rise to attachment and relishing, one immediately falls away": it is not that one can fall away from concentration in the higher bhūmis; rather, due to much attachment and relishing, one's lifespan is diminished, which is called 'immediately falling away'. This is falling away from rebirth.