Stokes V cross-epoch (2017-2023) light curve of J1019+65 phase-folded at a period of P₁ = 3.0742 h, corresponding to the f₁ peak seen in Fig. 2. The light curve is binned at intervals of 0.04 in phase and one full period corresponds to a phase interval of unity. The choice of starting phase is arbitrary. The green line represents the best sinusoidal fit using the computed LS model. The J1019+65 radio burst shown in Fig. A.3 is also plotted as a red line (with its width representing the duration of the burst) to indicate at which phase relative to the phase-folded light curves does it correspond to. Note: the burst shown in red only occurs in one epoch out of the whole dataset. The dashed black line at 0 mJy is drawn for clarity.