Redshift evolution of the intrinsic scatter of X-ray luminosity in scaling relations against optical mass proxies. The scatter of X-ray luminosity vs. velocity dispersion for the full sample is marked with blue squares, for the Gaussian sample with orange stars, for the Gaussian high-richness sample (λ ≥ 47.2) with magenta diamonds and the Gaussian high L_X sample (L_X ≥ 10⁴⁴ ergs s⁻¹) with small grey circles. The scatter of the X-ray luminosity vs. richness for the full sample is marked with black triangles and for the Gaussian high-velocity dispersion sample (σ_v ≥ 650 km s⁻¹) with light blue circles. For comparison, we show the linear fit to the evolution of scatter in L_X obtained using high-quality X-ray data on relaxed clusters from Mantz et al. (2016) with a red line. A larger scatter seen in our data at low redshifts is also seen in the analysis of Lopes et al. (2009). Lopes et al. (2009) X-ray luminosity vs. velocity dispersion relation at redshift z = 0.08 is marked with a red star, and their X-ray luminosity vs. M₅₀₀ at the same redshift is marked with a red triangle.