reaxff: abnormal concentration of OH during NVT

Hello all !
I have run a minimization for a system consisting of a crystal of orthorombic trinitrotoluene (226 molecules), and then
performed a NVT run (right after a temp/rescale) in 2500K for 20 ps.

I see that concentration of OH is half as that of water produced , which seems extremely awkward, for this species is very reactive !
OH shows up right at the begining and stays constant during the 20 ps NVT with concentration half of the water concentration (which is one of the stable thermodynamic products.)

Is this related to a malfunction of the force field ? or am I missing something

Concentration (density) is a function of volume. Who chose the
volume, you or LAMMPS? Nothing you listed makes it sound
as if LAMMPS did.