Top panel: 0.3–10 keV NICER X-ray light curve for 1ES 1927+654 since May 2018 (blue). Following the methodology of Masterson et al. (2022), we divided the long-term X-ray light curve of 1ES 1927+654 into distinct phases. Phase 1 is characterized by a super-Eddington state with rapid fluctuations in both X-ray luminosity and spectral parameters. Phase 2 maintains a stable super-Eddington luminosity near its peak. Phase 3 exhibits a gradual decline in X-ray luminosity and spectral parameters, returning to levels comparable to those observed prior to the outburst. Phase 1 is divided into two equal segments and phase 1b is between the two vertical dashed red lines in phase 1. Bottom panel: Observation data in phase 1b plotted as black points after binning all observations within three-day intervals for visual clarity. To enhance the visibility of the periodic signal, we applied the logarithmic function f(x) = A ⋅ log(Bx + C)+D and removed the long-term trend, connecting the data and model points with a smoothed curve. Note: this approach is intended solely for visual illustration of periodicity. Dashed gray vertical lines denote a period of 11.6 days.