Conductivity isotherms of (CdTe) (AgI)(0.5-x/2)(As2Te3)(0.5x-/2) glasses (0.0 <= x <= 0.15) reveal a nonmonotonic behavior with increasing CdTe content reminiscent of mixed cation effect in oxide and chalcogenide glasses. Nevertheless, the apparent similarity appears to be partly incorrect. Using Ag-110m tracer diffusion measurements, we show that semiconducting CdTe additions produce a dual effect: (i) decreasing the Ag+ ion transport by a factor of approximate to 200 with a simultaneous increase of the diffusion activation energy and (ii) increasing the electronic conductivity by 1.5 orders of magnitude. Consequently, the conductivity minimum at x = 0.05 reflects an ionic-to-electronic transport crossover; the silver-ion transport number decreases by 3 orders of magnitude with increasing x.