How homogeneous was the chemical enrichment of the Milky Way 13 gigayears ago?

We reanalyze the chemical composition of the metal-poorest tail of the Galactic halo using highly accurate atmospheric parameters Giribaldi et al. (2021, 2023) and cutting-edge 3D NLTE models Amarsi et al (2018). Most Mg/Fe versus Fe/H diagrams in the literature exhibit significant scatter at Fe/H -2 dex, often interpreted as evidence of inhomogeneous enrichment during the early phases of galaxy evolution Rossi et al. (2021). However, our analysis of observational data reveals that in the range -3. 5 < Fe/H < -2 dex, the Mg/Fe versus Fe/H distribution is relatively narrow. This finding suggests a low degree of stochastic enrichment in magnesium during these epochs in the Milky Way halo.