DESI (blue) and Euclid (green) spectra for the 16 objects that initially satisfy |z_vi−z_DESI|/(1 + z_DESI) > 0.15 among the 454 quasars in common with DESI DR1. The dashed red curve shows the quasar template spectrum evaluated at the final z_vi (scaled for display). Vertical dotted lines mark the expected observed wavelengths of common quasar emission lines at the final z_vi. Panels outlined in orange denote the five sources for which we revise z_vi after reinspection; for these, the initial (incorrect) z_vi is reported in parentheses after the updated z_vi in the panel title.