A fresh particle run now scatters the particles' initial Psi to the Eulerian mean before the first step, as a restart already did; the first IEM update previously relaxed toward a mean that had never seen the initial state. scalar_transport.iem_constant: 0 is accepted and switches micromixing off, carrying each particle's Psi bit-identically, and search_metrics.csv gains lost_psi_sum, the Psi removed with lost particles each step.