The photodissociation of HCl via the antibonding $2p^{-1}{\sigma }^{*}$ resonance occurs on the same 10-fs time scale as the Auger decay of the $2p$ vacancy. This means that the $v,v^{\prime }$ and ${\sigma }^{*}$ valence molecular orbitals involved in the electronic transition can significantly differ from the orbitals at the ground state equilibrium internuclear position. The non-relativistic $L-vv\prime$ resonant Auger (RA) spectrum based on the stationary Green’s function approach gives a good estimate of relative intensities of the three main spectral features in the $173-182$ eV emission energy range, but fails to reproduce highly resolved experimental data. We show that addition of the spin-orbit interaction of the $2{\pi }^{-2}{\sigma }^{*}$ and $5{\sigma }^{-1}2{\pi }^{-1}{\sigma }^{*}$ final states significantly improves the agreement for the spectral feature arising from the ${}^4\Pi {,}^2\Sigma$ and ${}^4\Sigma$ states that converge to the H + Cl${}^{+}{(}^{3}P)$ dissociation limit. Somewhat surprisingly, we found that the ${}^{3}P$ non-relativistic limit splits to five instead of three $3p^{-2}$(${}^3{P}_{0,1,2}$) dissociation limits of the Cl${}^{+}$ fragment at large internuclear distances. The similarity with the atomic case is broken because of a different nature of the ${}^2\Pi$ molecular state, which is populated by a weak participator Auger decay and converges to a different, significantly higher H${}^{+}$ + Cl(${}^2$P) dissociation limit. Our analysis shows that the remaining differences with an angle-integrated experimental spectrum are caused primarily by inaccuracies of the non-relativistic final state potentials and not by the one-center approximation of the spectator Auger transition rates. The potential slope differences are imprinted on the RA spectrum with a sensitivity and range depending on the duration of molecular dissociation with respect to the core-hole lifetime.