Spectroscopic variability of A2744-QSO1 as a function of time, with image A shown in blue, image B in red, and image C in green as in Fig. 3. –Top: Hβ rest-frame EW, presenting a drop of 22 ± 8% between images C and A. –Bottom: Hα rest-frame EW, presenting a drop of 18 ± 3% in the time between images C and A. We note that the variability is consistent in both broad Balmer lines, as can be expected, since they both originate from the broad-line region of A2744-QSO1. The EWs represent excellent indicators of variability, since they are insensitive to most systematics such as lensing, slit losses, and calibration.