  All phase transitions can be categorised into two different types: continuous
and discontinuous phase transitions. Discontinuous phase transitions are
normally accompanied with significant structural changes, and nearly all of
them have the kinetic pathway of nucleation and growth, if the system does not
suffer from glassy dynamics. Here, in a system of barrier-controlled reactive
particles, we find that the discontinuous freezing transition of a
non-equilibrium hyperuniform fluid into an absorbing state does not have the
kinetic pathway of nucleation and growth, and the transition is triggered by
long wavelength fluctuations. The transition rate decreases with increasing the
system size, which suggests that the metastable hyperuniform fluid is
kinetically stable in an infinitely large system. This challenges the common
understanding of metastability in discontinuous phase transitions. Moreover, we
find that the ``metastable yet kinetically stable'' hyperuniform fluid features
a new scaling in the structure factor $S(k \rightarrow 0) \sim k^{1.2}$ in 2D,
which is the third dynamic hyperuniform state in addition to the critical
hyperuniform state with $S(k \rightarrow 0) \sim k^{0.45}$ and the
non-equilibrium hyperuniform fluid with $S(k \rightarrow 0) \sim k^{2}$.
