Top: extracted local velocities for both nights (respectively blue and orange for the 2019-02-24 and 2019-03-17) with the best-fit model in black. The vertical dotted lines represent the contact points t₁ and t₄, the vertical loosely dotted lines represent the contact points t₂ and t₃, and the vertical dashed line represents mid-transit. Bottom left: local velocity residuals against the best-fit model for both nights. The vertical lines have the same significations as those in the top panel and the horizontal dashed line represents null velocity. Bottom right: distribution of the residuals in the bottom left panel.