Objects whose late-time detections are explained in the additional tests. The top four rows show the light curves of the objects where a previously undetected sibling transient as an explanation for the late-time observations could not be ruled out, with forced photometry light curves in the left-hand panels and the scene modelling photometry light curves in the right-hand panels. The 5σ detections are shown as bins with solid uncertainty regions and bins with hashed uncertainty regions are non-detections. The object whose late-time detections are caused by the host galaxy AGN, SN 2019vzf, is shown in the bottom row. The colours are as in Fig. 8 with g band in green, r band in orange, and i band in red.