  Magnetic doping is expected to open a band gap at the Dirac point of
topological insulators by breaking time-reversal symmetry and to enable novel
topological phases. Epitaxial (Bi$_{1-x}$Mn$_{x}$)$_{2}$Se$_{3}$ is a
prototypical magnetic topological insulator with a pronounced surface band gap
of $\sim100$ meV. We show that this gap is neither due to ferromagnetic order
in the bulk or at the surface nor to the local magnetic moment of the Mn,
making the system unsuitable for realizing the novel phases. We further show
that Mn doping does not affect the inverted bulk band gap and the system
remains topologically nontrivial. We suggest that strong resonant scattering
processes cause the gap at the Dirac point and support this by the observation
of in-gap states using resonant photoemission. Our findings establish a novel
mechanism for gap opening in topological surface states which challenges the
currently known conditions for topological protection.
