It is quite common for Chassidim to believe their Rebbe qualified to be Moshiach. At the Rebbe’s levaya, a letter is read confirming the Rebbe’s choice of a successor. Thereupon his Chasidim transfer their messianic hopes to the new leader of their Chassidus.
It is therefore deeply troubling that R’ M.M. Schneersohn did not designate a successor. Even an undisputed Moshiach such as Dovid HaMelech was a mortal man and had to choose one of his sons to continue the malchus. How could the Rebbe have been so irresponsible as to orphan his Chssidim? Is it any wonder they have been subject to troubling ideas about him?