Galaxies in the COSMOS field (grey dots) and 100 over-plotted realisations of the cosmic web in a redshift slice centred at z_phot ≃ 1.2. Upper panel: DISPERSE reconstruction performed directly on the masked galaxy distribution. The survey masks are visible as wide red regions completely devoid of galaxies, which induce artificial filamentary structures wrapping around their boundaries. Lower panel: Reconstruction after random in-painting of the masked regions prior to running DISPERSE (method adopted in this work), which mitigates these edge-induced artefacts.