  A recent and unexpected discrepancy between \textit{ab initio} simulations
and the interpretation of a laser shock experiment on aluminum, probed by X-ray
Thomson scattering (XRTS), is addressed. The ion-ion structure factor deduced
from the XRTS elastic peak (ion feature) is only compatible with a strongly
coupled out-of-equilibrium state. Orbital free molecular dynamics simulations
with ions colder than the electrons are employed to interpret the experiment.
The relevance of decoupled temperatures for ions and electrons is discussed.
The possibility that it mimics a transient, or metastable, out-of-equilibrium
state after melting is also suggested.
