  We predict an extreme sensitivity to the dissipative losses of the resonant
interaction of bulk phonons with a 2D defect in a solid. We show that the total
resonant reflection of the transverse phonon at the 2D defect, described
earlier without an account for dissipation, occurs only in the limit of
extremely weak dissipation and is changed into almost total transmission by
relatively weak bulk absorption. Anomalous surface absorption of the transverse
phonon, when one half of the incident acoustic energy is absorbed at the 2D
defect, is predicted for the case of "intermediate" bulk dissipation.
