If the crew selects a flex takeoff temperature (the assumed temperature used for thrust calculation) on the Multi-Function Control and Display Unit (MCDU) that is higher than the current Total Air Temperature (TAT), then the engine will run at the flex takeoff thrust rating. If the selected flex takeoff temperature is lower than the current TAT, then the engine will produce Maximum Continuous Thrust (MCT). This system allows for optimization of engine performance based on current environmental conditions and aircraft weight.
FADEC controls the engine over boost so no issues should practically occur as long as FADEC is working fine.