Top: Observed XRT LC of 241213A in the observer frame, likewise detected by EP/WXT 105 s earlier (see Table 2). Successful modelling with a different zero time yields $T_0={250}_{-50}^{+70}$ s. Bottom: Same LC as in the top panel, but with the reference time set to 250 s prior to the Swift trigger time. The LC is modelled with an SPL. The observed delay between soft X- and gamma rays is comparable with the value inferred from the prior activity model.