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.