Upper panel: phase-resolved deconvolved energy spectra extracted from the XMM-Newton observation during the V-shaped feature analyzed in Sect. 5. The best-fit model for all spectra is the one described in Sect. 4. The different selected phases for which the spectra are extracted are represented with the same color in the zoomed pulse profile in the inset (cyan points represent the pulse profile data for which no spectrum is displayed). Only EPIC-pn data are shown for clarity. The lower panel shows the residuals from the fit.