瑜伽論記 5.12

5.12

第二無倒翻初無倒應知，其相者謂得無漏定時將失有漏定時，如實知退，是名無倒。第三無倒漏定退時知退。

Regarding the second non-inversion, which inverts the first non-inversion, one should know its marks: that is, when one attains taintless absorption and is about to lose tainted absorption, knowing retrogradation in accordance with reality—this is called non-inversion. The third non-inversion: knowing retrogradation when tainted absorption retrogrades.