  Recent tritium beta decay experiments yield unphysical negative best-fit
values for the square of the neutrino mass. An unidentified bump-like excess of
counts few eV below the endpoint in the electron energy spectrum has been
tentatively recognized as the source of this anomaly. It is shown that the
repulsive potential acting on the emitted antineutrino and originating in its
coherent weak-interaction with the daughter atom may effectively account for
this excess.
