Help for BUG in the CVX optimization process：Linear Transformation of Convex Functions

I use the pow_abs &power CVX function to generate the PSD of the FIR filter. When I continue perform a linear transformation on the generated result, the command line reports an error.
My Code:

Note that the idft_mtx is a complex matrix.

A convex expression can be multiplied by a nonnegative constant, and the resulting expression will be convex. When a convex expression is multiplied by a non-real (complex) constant, the resulting expression is neither convex nor concave.