semiconductor equilibrium and steady state
The question is nonsense. Electrons are completely fungible &mdash; there is no way to distinguish one electron from another.

There's no meaningful way to talk about one set of electrons flowing in one direction across an interface and a different set flowing in the other direction &mdash; all you can talk about is the net flow, which as far as I can tell, is always zero in your scenario.

So yes, in that sense, the system is in equilibrium with respect to charge.

But if the temperature is rising and electron velocities are generally increasing, then it is not in thermal equilibrium.