QPO phase lag correction of three typical Insight-HXMT observations (reproduced from the data in Ma21). Each row represents the results of one observation. The FDPLS between 1–2.6 and 100–150 keV energy bands is shown in the left-hand panels. Middle panels are the original QPO energy-dependent phase lags. Right-hand panels are the intrinsic QPO energy-dependent phase lags after correction. The intrinsic QPO phase lags are obtained by subtracting the average of the phase lag of the BBN component (marked by the red dots in the left-hand panels) from the original QPO phase lag (the averaged value marked by the cyan dots in left-hand panels). The red arrows indicate the high-energy band data that we will model in Fig. 6. Error bars correspond to 1σ confidence intervals.