  We investigate the evolution of the physical extent of star formation of
$M_{\star}>10^9~M_{\odot}$ rapidly-quenching galaxies at $z=1.0-1.4$. We
measure the galaxy H$\alpha$ and stellar continuum sizes from their HST/WFC3
G141 grism spectroscopy and connect the galaxy sizes to time on their
evolutionary delayed-$\tau$ tracks determined in Noirot et al. (2022). Most
galaxies (10/13) have non-evolving H$\alpha$-to-continuum size-ratios
consistent with unity within the measurement uncertainties, suggesting an
homogeneous decline of star-formation in these galaxies despite a rapid
shut-down of their star formation. On the other hand, a handful (3/13) show
statistically smaller H$\alpha$ sizes compared to the stellar continuum as they
age and approach the blue-cloud/red-sequence transition region. This suggests
an outside-in shut-down of the star-formation (potentially driven by
environmental mechanisms) in these rapidly evolving galaxies as they move from
the blue cloud towards the red sequence.
