Normalized PSD computed using the Lomb-Scargle periodogram for the 1mm, 3mm, 7mm, 8mm, and R light curves, showing peak frequencies corresponding to characteristic timescales of 5.7, 5.4, 5.1, 4.2, and 6.8 years, respectively. These timescales are mostly in agreement with the 5–8 year timescale found in previous works. The false alarm probability in all cases is close to zero (≪0.1%), meaning that there is a very low probability that such a peak would be caused by a pure noise signal.