Yes, Prabhu Jagatbandhu is considered an incarnation of Krishna and Chaitanya Mahaprabhu by members of the Mahanam sect founded by him. Here is what this Mahanam sect website says:
Sri Sri Prabhu Jagatbandhu Sundar, the resident worshipped deity of the Mahanam Sampraday, is a condensed living idol of self-restraint, harinam and austere –practices. Like Sri Gour Hari, Prabhu was tall, bright complexioned, having all the divine traits and always clad in white robes. For the benefit of ignorant, He revealed his own identity by saying “The supreme Godhead and eternally original Sri Govinda is Sri Sri Krishna and Sri Sri Gouranga. One who is the total unification and energy of these two Lilas is Sri Sri Haripurush Jagatbandhu. That is only me - do you understand? -- the Lila combination of all things.” Prabhu Jagatbandhusundar was not a Guru in ordinary sense, he was Jagadguru, the Sureme Godhead incarnate, Lord Sri Krishna Himself.
Also, they think he's the fulfillment of a prophecy given in the Chaitanya Bhagavatam. Here is what K.L. Datta says in his biography of Prabhu Jagatbandhu:
In the Chaitanya-Bhagavat we find that Gour promised his devotees that he has two more manifestations of this kind "Kritan" (celestial joy) will be evident.
But I don't know of any Vaishnavas outside of the Mahanam sect that consider him an incarnation.