There are definitely indications that the stellar formation process continues down at planetary masses, below the deuterium fusion limit. Cha 110913-773444 probably was not formed in the same way as planets are, and thus there is a good case for calling it a brown dwarf.
Such formation-based definitions are on the other hand rather harder to work with on an observational, case-by-case basis, even though they definitely have utility in describing populations and systems of objects. The deuterium fusion limit provides a relatively easy-to-determine criterion for the division of planets and brown dwarfs, so there is also a good case for calling it a planet.
Personally I find the argument calling it a brown dwarf more persuasive, but certainly the matter is not settled in the astronomical community.