Temperature can both enhance and diminish the electrochemical performance of a battery, affecting both the thermodynamics and kinetics of a system. While focus has mostly been on the intercalating charge carrier, other degrees of freedom are equally as important and even so at higher temperatures. During the intercalation of LiFePO4, the redox couple Fe3+/Fe2+ charge compensates for the lithium while undergoing distortions that localize the electrons on specific iron sites. The placement of these electrons in the structure adds to the electronic degree of freedom which explains the high-temperature solid solution shown in the phase diagram. However, self-interaction errors of regular DFT calculations lead to a failure in predicting strongly localized electrons like those in the 3d states of iron. Adding a Hubbard U correction aims to locally penalize delocalization by endorsing integer orbital occupations, which may lead to metastable states. To further investigate this, occupation matrix control has been used together with DFT+U, showing that while the polarons initially would like to be close to lithium, the energy needed to occupy a state further away may still be reachable. This methodology showcases the numerical errors generated by approximations of DFT+U, which has been widely neglected, and will have to be considered when curating data for high-throughput multi-scale modelling.