From left to right: hysteresis loops between TiO-band temperature and M₁ velocity for three pseudo light cycles of Betelgeuse from Fig. 1. From top to bottom: different masks, with mask C2 probing the innermost atmospheric layer. Horizontal lines in all panels indicate the center-of-mass velocity (as in Fig. 1). The arrow indicates the direction of evolution along the hysteresis loops. Star symbols in the last column correspond to epochs JD 2 458 900.5 and JD 2 458 907.5, which are outside the shaded area defining Cycle 4 in Fig. 1. Black points in the last column denote the epoch of maximum light preceding the dimming event.