2D shift of the centre of gravity of the light beam carrying orbital angular momentum, which accompanies reflection from a lossy medium

It is shown that after reflection from a lossy medium the $s$- or $p$-polarized paraxial light beam carrying the orbital angular momentum suffers the 2D shift of the beam’s centre of gravity relative the geometric optic axis. The mutually orthogonal components of this shift are expressed through the real and imaginary parts of the common complex quantity. The features of the 2D vector, which describes the shift, are analyzed.