Relative difference of the aliased with respect to the de-aliased (see Section 3.1) matter power spectrum (left panel) and bispectrum in the squeezed limit (k₁ = k₂ = k; k₃ = k_f) (right panel). In the upper panels, we show the differences for initial conditions at z = 24, and in the lower panels, the results for the final snapshot at z = 0. The results for simulations with different PNG models are shown in different colours, as indicated in the legend. The shaded areas show the 1% difference around the higher-resolution reference simulation (Section 3.3). Aliasing introduces a spurious signal in the initial conditions (upper panels) for both the power spectrum and bispectrum, reaching 3% and 10% differences, respectively, in the g_NL = 10⁷ case. By late times (z = 0), these discrepancies are suppressed to below 1% across all scales and PNG parameter values considered.