Detail from Fig. 1 showing presence of low-order overtones long before the dimming. The upper panel shows variability of brightness and temperature; lower panel shows variability of velocity. The second and third red arrows denote the estimated times of maxima, which are delayed only by about 150 days from each other. The first red arrow denotes a possible local maximum outflow velocity of inner layers (C1–C3), while the two outermost layers appear not to have a local maximum of velocity. Thus, the behavior of the atmospheric layers slightly resembles the aftermath of dimming. If we had more data, we could see for how long the low-order overtones remained prominent.