Top: Evolution of the pulse period over time (see Sect. 3.2 for details). The dotted line represents a three-piece broken curve approximation of the data points. The dashed magenta line marks the transition to the equilibrium state. Middle: Long-term 0.5−10 keV light curve of J1301. Bottom: Zoomed-in view of segments of the long-term light curve after the transition. The light green zone indicates a flux range lower than the pre-transition quiescent flux. Green arrows indicate the times of the NuSTAR observations.