The word vāsanā (“material desires”) refers to dry speculative knowledge. Such speculative knowledge is only material. As confirmed in Śrīmad-Bhāgavatam (10.14.4), a person without devotional service who simply wants to know things (kevala-bodha-labdhaye) gains only dry speculative knowledge but no spiritual profit. This is confirmed in the Bhakti-sandarbha (111), wherein it is said:

jīvan-muktā api punar yānti saṁsāra-vāsanām
yady acintya-mahā-śaktau bhagavaty aparādhinaḥ

“Even though one is liberated in this life, if one offends the Supreme Personality of Godhead he falls down in the midst of material desires, of which dry speculation about spiritual realization is one.”

In his Laghu-toṣaṇī commentary on Śrīmad-Bhāgavatam (10.2.32), Jīva Gosvāmī says:

jīvan-muktā api punar bandhanaṁ yānti karmabhiḥ
yady acintya-mahā-śaktau bhagavaty aparādhinaḥ

“Even if one is liberated in this life, he becomes addicted to material desires because of offenses to the Supreme Personality of Godhead.”

A similar quotation from one of the Purāṇas also appears in the Viṣṇu-bhakti-candrodaya:

jivān-muktāḥ prapadyante kvacit saṁsāra-vāsanām
yogino na vilipyante karmabhir bhagavat-parāḥ

“Even liberated souls sometimes fall down to material desires, but those who fully engage in devotional service to the Supreme Personality of Godhead are not affected by such desires.”

These are references from authoritative revealed scriptures. If one becomes an offender to his spiritual master or the Supreme Personality of Godhead, he falls down to the material platform to merely speculate.