  We analyze the first-order formulation of the ghost-free bigravity model in
three-dimensions known as zwei-dreibein gravity. For a special choice of
parameters, it was argued to have an additional gauge symmetry and give rise to
a partially massless theory. We provide a thorough canonical analysis and
identify that whether the theory becomes partially massless depends on the form
of the stability condition of the secondary constraint responsible for the
absence of the ghost. Generically, it is found to be an equation for a Lagrange
multiplier implying that partially massless zwei-dreibein gravity does not
exist. However, for special backgrounds this condition is identically satisfied
leading to the presence of additional symmetries, which however disappear at
quadratic order in perturbations.
