We studied a bilayer system consisting of a two-dimensional electron gas in a GaAs/AlGaAs heterostructure and a thin superconducting Al film. Drag measurements were made by passing current through the two-dimensional electron gas layer and measuring the voltage induced in the superconducting layer. Unexplained peaks in drag voltage near the transition region were seen in previous similar experiments. We also detected a draglike voltage peak in the transition region. The signal is found to be nonintrinsic and due to radio frequency interference. The extremely nonlinear impedance of the Al in the transition region allows the interference to couple in this manner. We show a simplified analysis of the measurement system that reproduces the main features of our results.