Sometimes even a liberated person like Arjuna plays the part of a conditioned soul in order to play some important part. Similarly, Bhaktivinoda Thakura for some time was associating with the impersonalists and then he exhibited himself in his true color as pure devotee, exactly in the same way as Arjuna exhibited in the beginning as a conditioned soul, and then as a liberated soul. So there is nothing to be misunderstood in this connection. Krsna and His devotees sometimes play like that, as much as Lord Buddha, although an incarnation of Krsna, preached the philosophy of voidism. These things are conducted in terms of place, audience, time, etc. In the Caitanya-caritamrta it is said that the activities of the Vaisnava cannot be understood even by the greatest scholar. So we have to understand everything through the transparent via media of the spiritual master. So there is no doubt about it that Bhaktivinoda Thakura is eternal energy of Lord Sri Caitanya Mahaprabhu. And whatever he did, was just to suit the time, place, circumstances, and etc.
From Srila Prabhupada’s letter to Madhusudana, 20th November, 1968