  It is believed that the first star-forming galaxies are the main drivers of
cosmic reionization. It is usually assumed that there is a one-to-one
relationship between the star formation rate (SFR) inside a galaxy and the host
halo mass in semi-analytical/numerical modeling of large-scale reionization.
However, more accurate simulations and observations suggest that the SFR and
ionizing luminosity in galaxies may vary considerably even if the host halo
mass is the same. This astrophysical scatter can introduce an additional
non-Gaussianity in the HI 21-cm signal, which the power spectrum might not
capture adequately. In this work, we have studied the impact of the scatter on
the HI 21-cm bispectrum using semi-numerical simulations. Although the
fractional change in the HI 21-cm bispectra due to the scatter is found to be
more than a factor of $10$ at large scales ($k_1 \lesssim 1\, {\rm Mpc}^{-1}$)
for $z=7.4$, it is found to be statistically insignificant. However, at small
scales ($k_1\sim2.55$~Mpc$^{-1}$), we have found the impact due to the scatter
to be high in magnitude ($|\langle \Delta B \rangle/B_{\text{no-scatter}}| \sim
1$) and statistically significant ($|\langle\Delta B\rangle/\sigma_{\Delta B}|
\gtrsim 5$) at neutral fraction, $\overline{x}_{\rm HI}\sim 0.8$ for $z=7.4$.
The impact due to scatter is found to be even more prominent ($|\langle \Delta
B \rangle/B_{\text{no-scatter}}| \gtrsim 10$) at small scales for $z=10$ and
$\overline{x}_{\rm HI}\sim 0.8$, but with reduced statistical significance
($|\langle\Delta B\rangle/\sigma_{\Delta B}| \sim 3$), compared to $z=7.4$ at
the same neutral fraction. In the most optimistic scenario, SKA1-Low might be
able to detect these signatures of astrophysical scatter, at $\sim 3\sigma$ and
$\sim 5\sigma$ detection significance for $\overline{x}_{\rm HI} \sim$ 0.8 and
0.9 respectively, for the equilateral HI 21-cm bispectrum at $z=7.4$.
