This paper presents the first lattice simulation of a spectator axion-gauge system during inflation, where the axion experiences a momentary stage of fast roll. The simulation uses a novel hybrid numerical scheme to solve the fully nonlinear dynamics of the axion-gauge sector while treating the gravitational interaction between the axion and inflaton linearly. The study investigates both weak and strong backreaction regimes, revealing that backreaction significantly suppresses the growth of the gauge field and scalar perturbations. Despite this suppression, non-Gaussianity remains higher than in the minimal model where the axion coincides with the inflaton. The simulation also allows for the analysis of non-Gaussianity in scalar fluctuations, including higher-order statistics. The results highlight the need for robust simulations to test against data from gravitational wave interferometers and large-scale structure surveys. The study confirms the validity of the WKB approximation in the linear regime and shows that the lattice results agree with analytical predictions in the weak backreaction case. In the strong backreaction regime, the simulation reveals oscillatory behavior in the axion velocity and significant suppression of gauge field growth. The results provide insights into the nonlinear dynamics of the axion-gauge system and its phenomenological implications.This paper presents the first lattice simulation of a spectator axion-gauge system during inflation, where the axion experiences a momentary stage of fast roll. The simulation uses a novel hybrid numerical scheme to solve the fully nonlinear dynamics of the axion-gauge sector while treating the gravitational interaction between the axion and inflaton linearly. The study investigates both weak and strong backreaction regimes, revealing that backreaction significantly suppresses the growth of the gauge field and scalar perturbations. Despite this suppression, non-Gaussianity remains higher than in the minimal model where the axion coincides with the inflaton. The simulation also allows for the analysis of non-Gaussianity in scalar fluctuations, including higher-order statistics. The results highlight the need for robust simulations to test against data from gravitational wave interferometers and large-scale structure surveys. The study confirms the validity of the WKB approximation in the linear regime and shows that the lattice results agree with analytical predictions in the weak backreaction case. In the strong backreaction regime, the simulation reveals oscillatory behavior in the axion velocity and significant suppression of gauge field growth. The results provide insights into the nonlinear dynamics of the axion-gauge system and its phenomenological implications.