俱舍論記 28.117

28.117

「第四染中至所染污故」者，此明第四染定無捨、念二，有中受、定。故《正理》云「第四染中無捨、念淨，彼為煩惱所染污故。由此第四染唯二支。」

"In the fourth defiled [dhyāna] [...] because it is defiled [by afflictions]": this clarifies that the fourth defiled samādhi lacks equanimity (upekṣā) and smṛti, and possesses neutral feeling and samādhi. Thus the Nyāyānusāra says: "In the fourth defiled [dhyāna] there is no purity of equanimity and mindfulness, because it is defiled by defilements. Therefore the fourth defiled [dhyāna] has only two factors."