We present the first leading hadron suppression predictions in $$\textrm{Pb}+\textrm{Pb}$$ $\text{Pb}+\text{Pb}$ and $$\textrm{p}+\textrm{Pb}$$ $\text{p}+\text{Pb}$ collisions from a convolved radiative and collisional energy loss model in which partons propagate through a realistic background and in which the radiative energy loss receives a short pathlength correction. We find that the short pathlength correction is small for D and B meson $$R_{AA}(p_T)$$ $R_{\mathrm{AA}}\left(p_T\right)$ in both $$\textrm{Pb}+\textrm{Pb}$$ $\text{Pb}+\text{Pb}$ and $$\textrm{p}+\textrm{Pb}$$ $\text{p}+\text{Pb}$ collisions. However the short pathlength correction leads to a surprisingly large reduction in suppression for $$\pi $$ $\pi$ mesons in $$\textrm{p}+\textrm{Pb}$$ $\text{p}+\text{Pb}$ and even $$\textrm{Pb}+\textrm{Pb}$$ $\text{Pb}+\text{Pb}$ collisions. We systematically check the consistency of the assumptions used in the radiative energy loss derivation-such as collinearity, softness, and large formation time-with the final numerical model. While collinearity and softness are self-consistently satisfied in the final numerics, we find that the large formation time approximation breaks down at modest to high momenta $$p_T \gtrsim 30~\textrm{GeV}$$ $p_T\gtrsim 30\text{GeV}$ . We find that both the size of the small pathlength correction to $$R_{AA}(p_T)$$ $R_{\mathrm{AA}}\left(p_T\right)$ and the $$p_T$$ $p_T$ at which the large formation time assumption breaks down are acutely sensitive to the chosen distribution of scattering centers in the plasma.