PL-based external radiative efficiency (ERE) and implied open-circuit voltage (iV OC) metrics were introduced for thin-film solar absorbers to better understand the voltage deficit and diagnose losses in solar cells. Traditionally, elevated ERE and iV OC measurements are associated with diminished recombination within the solar device, a rationale heavily reliant on the assumption of a uniform bandgap and high carrier mobilities in the absorber. In this study, we investigate the possible reasons of elevated iV OC in realistic CdSeTe absorbers with a graded Se profile. By employing light-induced transient grating measurements, we reveal that hole mobility significantly decreases—by more than an order of magnitude—with increasing Se content. Using detailed numerical models of iV OC, we examine how the bandgap nonuniformity and the reduced hole mobility within graded CdSeTe absorbers influence iV OC measurements. We show that high iV OC may result from inflated quasi-Fermi-level splitting in the front region of a CdSeTe absorber with slow hole transport. Based on our results, we conclude that the iV OC metric (or ERE metric) for graded CdSeTe devices may be misleading, is not suitable for quantitative assessments, and should not be used as a sole metric of absorber quality. We discuss possible ways to extract useful information from the iV OC–V OC gap by supplementing the front-side illumination measurements with back-side illumination measurements.