It has been shown logically that falling from Vaikuṇṭha is not possible under any circumstances. Nor is there any scriptural evidence to support such an event. However, there are many scriptural texts to the effect that it is impossible to fall down from the spiritual world, regardless of whether one has resided there eternally or has attained it after many lifetimes in the mundane world.
No one can enter or remain in Vaikuṇṭha unless he has attained devotion for the Lord. Lord Ṛṣabhadeva confirms this: When the living being is covered by tamo-guṇa, his mind is subject to result-oriented action. Therefore, the jīva cannot be released from attachment to the body until love dawns for Me, Lord Vāsudeva.
(4 and 5) A perfected devotee never commits an offense. Offenses are committed due to ignorance, resulting from forgetfulness of the Lord. Offense (aparādha) means an act that causes displeasure. A siddha devotee never forgets the Lord, and he never desires to displease the Lord; he thus never commits offenses, knowingly or unknowingly.
(2) There is no possibility of committing sin in the spiritual world. Sin and piety exist only in the material world, both being products of the guṇas of nature. A devotee in the spiritual world is situated in his eternal inherent nature (svarūpa), free from material covering or ignorance...
Continuation of the commentary: Transcendental entities do not get converted from spiritual to material. Moreover, Vaikuṇṭha is unlimited—it has no bounds. It is anantam, as stated in the Bhāgavatam. This abode is truth, consciousness, the unlimited, the indestructible spiritual effulgence that silent sages witness in their trance
Commentary by Satyanarayana Dasa: In this anuccheda, Śrīla Jīva Gosvāmī proves that no one falls to the material world from Vaikuṇṭha. In other words, Vaikuṇṭha is acyuta-padam, a place devoid of falldown. Anuccheda 49 established that Vaikuṇṭha is not attained by karma ...
(3) No one falls down from that abode (tato’skhalanam). Śrī Kapiladeva says: Thereafter, they do not hanker after any opulence stored for them by My māyā, nor for the eight ensuing yogic paranormal powers, nor even for the transcendental glory of God, and yet these benign gifts become effortlessly available to them in My supreme abode