Azimuthal correlation distributions in the 30$-$50% centrality class of Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ $\mathrm{TeV}$ and for the interval $0.20< z_{\rm T}< 0.30$, for isolated-narrow clusters triggered in the range $20< p_{\rm T}^{\rm trig}< 25$ GeV/$c$, with charged-particle tracks in the same collision ("Same event", black-open circles) or in a different collision ("Mixed event", red without marker). The result of subtracting the mixed-event distribution is shown in blue-full circles. The vertical bars indicate the statistical uncertainties.