CC Madhya 10.113

bhakti-siddhānta-viruddha, āra rasābhāsa
śunite nā haya prabhura cittera ullāsa
Synonyms: 
bhakti-siddhānta — conclusive statements about the science of devotional service; viruddha — opposing; āra — and; rasa-ābhāsa — overlapping of transcendental mellows; śunite — to hear; — not; haya — becomes; prabhura — of Śrī Caitanya Mahāprabhu; cittera — of the heart; ullāsa — jubilation.
Translation: 
Śrī Caitanya Mahāprabhu was never pleased to hear books or verses opposed to the conclusive statements of devotional service. The Lord did not like hearing rasābhāsa, the overlapping of transcendental mellows.
Purport: 

Bhakti-siddhānta-viruddha refers to that which is against the principle of unity in diversity, philosophically known as acintya-bhedābheda — simultaneous oneness and difference — whereas rasābhāsa is something that may appear to be a transcendental mellow but actually is not. Those who are pure Vaiṣṇavas should avoid both these things opposed to devotional service. These misconceptions practically parallel the Māyāvāda philosophy. If one indulges in Māyāvāda philosophy, he gradually falls down from the platform of devotional service. By overlapping mellows (rasābhāsa) one eventually becomes a prākṛta-sahajiyā and takes everything to be very easy. One may also become a member of the bāula community and gradually become attracted to material activities. Śrī Caitanya Mahāprabhu has therefore advised us to avoid bhakti-siddhānta-viruddha and rasābhāsa. In this way the devotee can remain pure and free from falldowns. Everyone should try to remain aloof from bhakti-siddhānta-viruddha and rasābhāsa.