  In Jiang et al. (2020), we reported a possible bright flash (hereafter
GN-z11-flash) from a galaxy GN-z11 at z ~ 11. Recently, Steinhardt et al.
(2021; arXiv:2101.12738) found 27 images with transient signals in Keck MOSFIRE
archival data and claimed that GN-z11-flash was more likely from a moving
object in our Solar system. We show that the Steinhardt et al.'s definition of
the chance probability and their methodology of finding GN-z11-flash-like
transients are problematic in several aspects. In particular, none of their
transients is analogous to GN-z11-flash, and none of them is positionally
coincident with a known object in their imaging data. In Jiang et al., we
performed a comprehensive analysis of the origin of GN-z11-flash and ruled out,
to the best of our knowledge, the possibility of known man-made objects or
moving objects in the Solar system, based on all available information and our
current understanding of these objects. Steinhardt et al. did not use such
information and did not analyse the GN-z11-flash event itself. The majority of
their transients are apparently low-Earth orbit satellites or aircrafts.
Therefore, their analysis can neither prove nor disprove our results. Finally,
we present a method to estimate the chance probability of finding
GN-z11-flash-like transients in archival data. Based on this method and the
archival data used by Steinhardt et al., we obtain a loose upper limit of the
probability that actually support the original results of Jiang et al. (2020).
