Residuals versus LMJM for the fiber with the most external-reference matches. The y-axis shows ﹩{\rm{R}}{{\rm{V}}}_{{\rm{corr}}}^{{\rm{sp}}}-{\rm{R}}{{\rm{V}}}_{{\rm{ref}}}﹩, i.e., the MRS RV after the spectrograph–exposure correction relative to the external reference. Blue points use Gaia-corrected RVs and orange points use APOGEE DR17 RVs; point darkness encodes the weighted-median weight (darker = higher weight). Black filled circles show the weighted-median residual for each fiber–time unit with its σ error bar. Known and candidate double-lined spectroscopic binaries from M. Kovalev et al. (2024) are excluded. The remaining coherent time dependence motivates the second-level fiber–time correction.