गोविन्द भाष्य (श्रील बलदेव विद्याभूषण - अचिन्त्यभेदाभेद वेदान्त ब्रह्मसूत्र भाष्य सटीक)

His conclusion.
Sūtra 52
evaṁ mukti-phalāniyamas tad-avasthāvadhṛtes tad-avasthāvadhṛteḥ
evam—thus; mukti—of liberation; phala—the result; a—not; niyamaḥ—rule;
tat—of that; avasthā—state of being; avadhṛteḥ—because of the determination.
In the same way there is no specific rule about liberation, for it depends on the
circumstances.
Purport by Śrīla Baladeva Vidyābhūṣaṇa
As there is no rule about transcendental knowledge, so there is no rule that a
person situated in transcendental knowledge and striving for liberation must attain
liberation in the same lifetime. When there are no longer any obstacles, then a
person situated in transcendental knowledge attains liberation when he dies. This
means when there are no longer any past karmic reactions. When there are no
karmic reactions remaining, then one attains liberation at the moment of death.
When there are karmic reactions remaining one does not attain liberation at the
moment of death. Why is that? The sūtra explains, "tad-avasthāvadhṛteḥ" (for it
depends on the circumstances). In the Chāndogya Upaniṣad (6.14.2) it is said:
ācāryavān puruṣo veda tasya tāvad eva ciraṁ yāvan na vimokṣye atha sampatsye
"One who approaches a bona fide spiritual master can understand everything
about spiritual realization.* When his past karmic reactions are exhausted he at
once attains liberation."
In this way the Chāndogya Upaniṣad affirms that one attains liberation when
his past karmic reactions are exhausted. In the Nārāyaṇādhyātma it is said:
vidvān amṛtam āpnoti
nātra kāryā vicāraṇā
avasannaṁ yadārabdhaṁ
karma tatraiva gacchati
na ced bahūni janmāni
prāpyaivānte na saṁśayaḥ