Evolution of the rms amplitude of the QPO in the 2.0 − 12.0 keV band (top left) and in the 0.3 − 2.0 keV band (bottom left) as MAXI J1820+070 transitions out of the HSS. The right panel displays the evolution of the phase lags of the QPO for the 2.0 − 12.0 keV band with respect to the 0.3 − 2.0 keV band. The rms and phase lags are derived from the fitted Lorentzian in our model (see Sect. 3). In the three panels, the horizontal bars correspond to the time duration of each observation, while the vertical bars are the actual 1 − σ errors of each quantity. The colour gradient depicts the centroid frequency of the QPO.